A test method for surcharge load of large-span full-scale prestressed slab rib beams in underground spaces

Abstract

This invention relates to the field of structural testing technology in building engineering, and particularly to a method for a full-scale prestressed slab rib beam surcharge test in underground spaces. It aims to solve problems such as size effect distortion, unsuitability of the reaction system to the underground environment, lack of monitoring of key components, and incomplete loading data in existing scaled-down tests. The method includes: constructing a full-scale prestressed slab rib beam test body and an underground-adaptive reaction system based on actual engineering geology and structure; deploying sensors at key components such as the mid-span of the slab, rib beam supports, and prestressing tendon anchorage zones; surcharged in stages using hydraulic jacks, holding the load at each stage until deformation stability; simultaneously collecting strain, displacement, and prestress data; processing the data and analyzing stiffness evolution, prestress effect, stress redistribution, and failure modes to assess the structural bearing capacity and safety reserve. This invention reproduces actual engineering conditions, providing accurate and comprehensive data that can directly guide the design optimization and safe application of prestressed slab rib beams in underground spaces.

Description

Technical Field

[0001] This invention relates to the field of structural testing technology in building engineering, specifically a method for load testing of large-span full-scale prestressed slab rib beams in underground spaces. Background Technology

[0002] With the expansion of underground space development, large-span prestressed slab rib beams are widely used in underground parking garages, integrated utility tunnels, and other engineering projects due to their advantages such as high load-bearing capacity, excellent space utilization, and low material consumption. Their mechanical properties directly affect engineering safety. However, current load testing methods for this structure have significant limitations:

[0003] Existing tests mostly use scaled-down models, which are affected by size effects. Their stiffness and failure modes differ significantly from those of actual structures. Furthermore, they often ignore underground geological constraints and spatial limitations, and the reaction system is not adapted to the underground environment, resulting in a disconnect between the test scenario and engineering reality.

[0004] Monitoring often focuses on conventional displacement and strain indicators, lacking targeted monitoring of key parts such as rib beam supports and prestressed tendon anchorage zones. Improper sensor selection or installation can also lead to data distortion.

[0005] Loading is often done in a one-time or insufficient load-bearing stage, which easily leads to the loss of data on the elastic-elastoplastic transition stage, and the identification of failure mode and bearing capacity limit becomes ambiguous.

[0006] Data processing often remains at the level of simple screening, and performance evaluation only focuses on bearing capacity, which is insufficient to fully support engineering design optimization and safety management. There is an urgent need for precise testing methods adapted to the characteristics of underground spaces.

[0007] Therefore, a test method for surcharge load testing of large-span full-scale prestressed slab rib beams in underground spaces is proposed to address the above problems. Summary of the Invention

[0008] The purpose of this invention is to provide a method for surcharge testing of large-span, full-scale prestressed slab rib beams in underground spaces, in order to solve the problems mentioned in the background art.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] A method for surcharge testing of large-span full-scale prestressed slab rib beams in underground spaces includes the following steps:

[0011] S1. Test System Construction: Within the underground space, a full-scale prestressed slab-ribbed beam test body is constructed based on the actual engineering structure and geological conditions. The prestressed slab-ribbed beam test body includes a slab, ribbed beams, prestressing tendons, and an anchoring system. A reaction system is constructed around the prestressed slab-ribbed beam test body. The reaction system provides reaction force through a spatial structure set above the test body, or through rigid reaction force members anchored to the side walls and bottom slab of the underground space.

[0012] S2. Measurement system setup: Measurement sensors are set up at key locations of the prestressed slab rib beam test body. Key locations include the mid-span of the slab, the slab support, the mid-span of the rib beam, the rib beam support, the prestressing tendon anchorage zone, and the prestressing tendon curve segment.

[0013] S3. Graded loading: Through the reaction system, hydraulic jacks are used to apply graded loading to the surface of the prestressed slab rib beam test body. After each load is applied, the load is held until the structural deformation stabilizes.

[0014] S4. Real-time data monitoring and acquisition: During the staged loading process, data from all measurement sensors are acquired synchronously to obtain structural response data;

[0015] S5. Test Data Processing and Performance Evaluation: Based on structural response data, the stiffness evolution, prestressing effect, stress redistribution process and failure mode of the prestressed slab rib beam test specimens are analyzed to evaluate the structural performance.

[0016] As a preferred option, the construction of the experimental system in step S1 specifically includes the following steps:

[0017] S1-1. Foundation treatment and foundation construction: Based on the actual engineering geological conditions, the foundation of the underground space test area is compacted and leveled, and then the concrete foundation of the prestressed slab rib beam test body is constructed according to the design drawings.

[0018] S1-2, Construction of full-scale test body: On the completed foundation, the reinforcement binding and formwork support of the rib beams are carried out in sequence, the bottom reinforcement of the slab is laid, the prestressing tendon duct is reserved, and then the overall concrete is poured and cured to form a full-scale prestressed slab rib beam test body that is the same as the actual structure of the project.

[0019] S1-3. Installation of the prestressing system: After the concrete of the test body reaches the design strength, the prestressing tendons are inserted and tensioned and anchored using the anchoring system to establish the initial prestress.

[0020] S1-4. Construction of the reaction system: Select the reaction supply method according to the underground space conditions. When the upper space structure is used, install the force transmission support and reaction beam on the plate-rib beam test body. When the side wall and bottom plate are used, anchor the reaction frame to the side wall and bottom plate of the underground space through ground anchors or rigid columns to form a complete loading reaction system.

[0021] As a preferred option, the deployment of the measurement system in step S2 specifically includes the following steps:

[0022] S2-1. Key component identification: Based on the design drawings and structural stress characteristics of the prestressed slab rib beam test body, the specific locations of key components are accurately identified on the surface of the test body. Key components include the mid-span of the slab, the slab support, the mid-span of the rib beam, the rib beam support, the prestressed tendon anchorage zone, and the prestressed tendon curved segment.

[0023] S2-2, Sensor Selection and Preparation: Based on the stress and deformation measurement requirements of key parts, select the corresponding strain sensors, displacement sensors and prestress monitoring sensors, and complete the calibration and initialization settings of the sensors.

[0024] S2-3. Sensor Installation and Fixing: At the marked key locations, use adhesive or mechanical fixing methods to install the sensor on the surface or inside the test body at the preset position, ensuring that the sensor is in close contact with the structure and does not affect the stress on the structure.

[0025] S2-4. Data Acquisition System Connection: Connect the installed sensors to the data acquisition equipment via signal lines to form a complete measurement network, and perform system debugging to verify the stability and accuracy of data transmission.

[0026] As a preferred embodiment, the staged loading application in step S3 specifically includes the following steps:

[0027] S3-1. Determination of loading scheme: Based on the design load and expected performance of the prestressed slab rib beam test body, determine the load level, holding time and deformation stability standard of graded loading.

[0028] S3-2, Initial Load Application: Using the reaction system, hydraulic jacks are used to apply the first load to the surface of the prestressed slab rib beam test body, and the initial loading data is recorded.

[0029] S3-3, Load Holding and Deformation Monitoring: After each load level is applied, a load holding operation is performed, and the deformation data of the test body is monitored in real time using a measurement system until the deformation rate is lower than the preset threshold, at which point the structure is determined to be stable.

[0030] S3-4. Subsequent load application: After the structural deformation stabilizes, the next load is applied based on the deformation results of the previous load, and the load holding and deformation monitoring process is repeated.

[0031] S3-5. Loading Termination Judgment: When the load is applied to the maximum design load or the test specimen shows signs of failure, stop loading and record the final load state and deformation data.

[0032] As a preferred approach, the real-time data monitoring and acquisition in step S4 specifically includes the following steps:

[0033] S4-1. Data Acquisition System Initialization: Start and configure the data acquisition system before the start of graded loading, and set the sampling frequency, range and data storage parameters of all measurement sensors.

[0034] S4-2, Synchronous Trigger Acquisition: At the same time as each load loading command is issued, a synchronous trigger signal is sent to the data acquisition system to start synchronous acquisition of data from all measuring sensors;

[0035] S4-3 Real-time data stream monitoring: During the acquisition process, a real-time data stream channel is established from the sensor to the data acquisition device to display and monitor the acquired strain, displacement and prestress data in real time.

[0036] S4-4 Data Quality and Integrity Verification: Based on the real-time monitored data stream, the validity of the data is judged, signal anomalies or data loss are marked, and supplementary measurements or sensor status adjustments are performed during the load stabilization phase.

[0037] S4-5. Generation and storage of hierarchical datasets: After the end of each load holding phase, all sensor data collected in this phase are classified and integrated according to load level, time series and sensor location to generate and store the structural response dataset corresponding to that load level.

[0038] As a preferred approach, step S5, which involves experimental data processing and performance evaluation, specifically includes the following steps:

[0039] S5-1, Structural response data preprocessing: Filter and remove outliers from the raw structural response data collected in step S4 to obtain a clean strain, displacement and prestress data sequence.

[0040] S5-2, Load-deformation relationship establishment: Based on the clean data sequence obtained in S5-1, the load-deformation curves of the prestressed slab rib beam test body during the graded loading process are plotted, including the load-displacement relationship between the mid-span of the slab and the mid-span of the rib beam.

[0041] S5-3, Stiffness Evolution Analysis: Calculate the equivalent stiffness under each load level based on the load-deformation curve, and analyze the evolution law of stiffness with increasing load.

[0042] S5-4. Prestressing Effect Analysis: Based on the analysis of clean prestressing data sequence, the stress change of prestressing tendons during surcharge is analyzed to evaluate the contribution of prestressing to the structural stiffness and bearing capacity.

[0043] S5-5, Stress Redistribution Process Analysis: The stress distribution of key parts is calculated using clean strain data sequences, and the stress redistribution process from the plate to the rib beam during loading is analyzed.

[0044] S5-6. Failure Mode Identification: Combining the results of stiffness evolution analysis, prestress effect analysis, and stress redistribution process analysis, identify the failure initiation point and failure mode of the test specimen.

[0045] S5-7 Structural Performance Assessment: Based on the failure mode identification results and the analysis results of S5-3, S5-4, and S5-5, the overall structural performance of the prestressed slab rib beam test specimen is comprehensively evaluated. The overall structural performance of the prestressed slab rib beam test specimen includes bearing capacity, deformation capacity, and safety reserve.

[0046] As can be seen from the technical solution provided by the present invention above, the beneficial effects of the surcharge test method for large-span full-scale prestressed slab rib beams in underground spaces provided by the present invention are:

[0047] To improve the authenticity of experiments and the reliability of data, and to accurately reflect the actual performance of engineering projects:

[0048] This invention constructs a full-scale prestressed slab-ribbed beam test specimen in an underground space based on actual engineering structures and geological conditions. It completely replicates the real structural morphology of the slab, ribbed beam, prestressing tendons, and anchorage system. Furthermore, the foundation treatment and construction match actual engineering geological parameters, avoiding mechanical behavior distortion caused by size effects in scaled-down models. Simultaneously, the reaction system simulates the reaction support environment under real loads through two construction methods adapted to underground space conditions (force transmission from the upper spatial structure and anchorage between the sidewalls and the bottom slab). This ensures a high degree of consistency between the experimental process and the actual stress scenario in engineering. The resulting structural response data accurately reflects the actual mechanical performance of large-span prestressed slab-ribbed beams in underground spaces, providing reliable data support for engineering applications.

[0049] Achieve multi-dimensional and accurate monitoring to ensure the comprehensiveness and effectiveness of data:

[0050] In the deployment of the measurement system, this invention precisely matches strain sensors, displacement sensors, and prestress monitoring sensors to key stress-bearing locations such as the mid-span of the slab, slab supports, mid-span of the rib beams, rib beam supports, prestressed tendon anchorage zones, and prestressed tendon curve segments. Through sensor calibration, standardized installation and fixing, and system debugging, it ensures that the sensors are tightly fitted to the structure without affecting the stress distribution, and that data transmission is stable and accurate. During the graded loading process, all sensors are simultaneously triggered to collect data, the data stream is monitored in real time, and data quality is verified. Outliers are removed, and missing data is supplemented, ultimately forming a multi-dimensional clean dataset covering stress, displacement, and prestress changes. This comprehensively captures the key responses of the structure at different load stages, providing a complete and effective data foundation for subsequent performance analysis.

[0051] Complete capture of structural mechanical behavior, accurate identification of failure modes and performance boundaries:

[0052] This invention employs a graded loading method, setting load levels, holding times, and deformation stability standards based on design loads and expected performance. Each load level is held until deformation stability is achieved, avoiding sudden structural failure caused by a single loading and the loss of crucial data from the elastic-elastoplastic transition phase. This loading method allows for the complete recording of the load-deformation curve of the structure from initial stress to near failure. Combined with stiffness evolution analysis, it clarifies the critical load for stiffness reduction; stress redistribution analysis reveals changes in the force transmission path; and prestress effect analysis assesses the contribution of prestress. Finally, by combining multi-dimensional data, it identifies the failure initiation point and failure mode (such as bending failure and shear failure), accurately defining the structure's bearing capacity limit and performance boundary, providing a clear basis for judging the structural safety status.

[0053] Provides scientific and comprehensive performance evaluation to directly guide engineering design and safety applications:

[0054] In the experimental data processing stage, this invention obtains clean data through filtering and outlier removal, constructs load-deformation relationships, and analyzes the data from four core dimensions: stiffness evolution, prestressing effect, stress redistribution, and failure mode. Ultimately, it comprehensively evaluates the structure's bearing capacity, deformation capacity, and safety reserve. This evaluation process not only clarifies whether the structure meets design requirements but also reveals weak points in the structure's stress distribution (such as stress concentration areas and load points with sudden stiffness drops). It provides direct scientific guidance for the engineering optimization design (such as adjusting prestressing tendon configuration and optimizing cross-sectional dimensions), construction quality control (such as prestressing tensioning accuracy and concrete curing standards), and safe operation and maintenance (such as load limit setting and damage monitoring focus) of large-span prestressed slab-ribbed beams in underground spaces. This effectively reduces engineering application risks and ensures the safety of underground space structures. Attached Figure Description

[0055] Figure 1 This is a schematic diagram of the steps of the test method for large-span full-scale prestressed slab rib beams in underground space according to the present invention. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0057] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific embodiments.

[0058] like Figure 1 As shown, this embodiment of the invention provides a method for surcharge testing of large-span full-scale prestressed slab rib beams in underground spaces, comprising the following steps:

[0059] S1. Test System Construction: Within the underground space, a full-scale prestressed slab-ribbed beam test body is constructed based on the actual engineering structure and geological conditions. The prestressed slab-ribbed beam test body includes a slab, ribbed beams, prestressing tendons, and an anchoring system. A reaction system is constructed around the prestressed slab-ribbed beam test body. The reaction system provides reaction force through a spatial structure set above the test body, or through rigid reaction force members anchored to the side walls and bottom slab of the underground space.

[0060] S2. Measurement system setup: Measurement sensors are set up at key locations of the prestressed slab rib beam test body. Key locations include the mid-span of the slab, the slab support, the mid-span of the rib beam, the rib beam support, the prestressing tendon anchorage zone, and the prestressing tendon curve segment.

[0061] S3. Graded loading: Through the reaction system, hydraulic jacks are used to apply graded loading to the surface of the prestressed slab rib beam test body. After each load is applied, the load is held until the structural deformation stabilizes.

[0062] S4. Real-time data monitoring and acquisition: During the staged loading process, data from all measurement sensors are acquired synchronously to obtain structural response data;

[0063] S5. Test Data Processing and Performance Evaluation: Based on structural response data, the stiffness evolution, prestressing effect, stress redistribution process and failure mode of the prestressed slab rib beam test specimens are analyzed to evaluate the structural performance.

[0064] In this embodiment, step S1 aims to construct a full-scale test platform and stable loading support system that matches the actual engineering conditions of the underground space. By replicating the real structural form, geological foundation, and prestressing state, it provides a test environment that conforms to the actual engineering situation for subsequent graded loading and data monitoring, ensuring that the test results can accurately reflect the real mechanical performance and structural response of the large-span prestressed slab rib beam in the underground space. The specific steps in constructing the test system in step S1 include the following:

[0065] S1-1. Foundation Treatment and Construction:

[0066] Foundation condition replication: Based on the actual engineering geological conditions of the underground space test area, the foundation is compacted in layers using tamping equipment to eliminate voids inside the foundation. At the same time, the foundation surface is leveled using leveling equipment to make the bearing capacity and deformation characteristics of the foundation match the actual engineering foundation parameters, thus avoiding distortion of the test body's stress due to foundation differences.

[0067] Concrete foundation construction: According to the requirements of the design drawings of the prestressed slab rib beam test body, tie the foundation steel bars and support the foundation formwork on the treated foundation. Then pour the concrete and carry out standard maintenance to form a concrete foundation consistent with the actual engineering foundation structure, ensuring that the foundation stiffness and bearing capacity meet the support requirements of the test body's self-weight and subsequent stacking loads, and providing a stable stress-bearing base for the test body;

[0068] S1-2, Full-scale test body construction:

[0069] Rib beam structure construction: On the already maintained concrete foundation, carry out the steel bar tying operation of the rib beam according to the design drawings, ensuring that the steel bar specifications, spacing, and anchorage length meet the requirements of the actual project; after tying, support the rib beam formwork, and the formwork needs to have sufficient stiffness to resist the lateral pressure during concrete pouring and prevent the formwork from deforming and affecting the forming size of the rib beam;

[0070] Slab structure and duct reservation construction: After the rib beam formwork is supported, lay the bottom steel bars of the slab, ensuring that the bidirectional spacing is uniform and the steel bars are reliably connected to the rib beam steel bars; at the same time, preset the prestressed tendon ducts inside the slab and rib beam according to the design direction and position of the prestressed tendons. The duct material and diameter need to match the specifications of the prestressed tendons used in the actual project to ensure the smooth passing of the subsequent prestressed tendons;<>

[0071] Integral pouring and maintenance: After completing the above processes, carry out integral concrete pouring for the rib beam and slab. During the pouring process, use vibrating equipment to ensure the compactness of the concrete and avoid defects such as honeycombing and pockmarks; after pouring, cover with moisture-proof materials for standard maintenance until the concrete strength reaches the design strength grade, forming a full-scale prestressed slab rib beam test body that is completely consistent with the actual engineering structure size, material, and connection form of the underground space, ensuring the structural authenticity of the test body;

[0072] S1-3, Prestressing system installation:

[0073] Prestressed tendon passing: After the concrete strength of the test body reaches the design specified strength value, pass the prestressed tendons into the preset prestressed tendon ducts according to the design path. During the passing process, avoid excessive friction between the prestressed tendons and the duct walls to cause damage, ensuring that the positions of the prestressed tendons are consistent with the design drawings and providing an accurate stress-bearing path for subsequent tensioning;

[0074] Prestressed tensioning and anchoring: Use the tensioning equipment supporting the anchoring system to carry out staged tensioning operations on the prestressed tendons according to the prestressed tensioning process of the actual project (such as tensioning sequence, tensioning control stress value); after tensioning to the design control stress, fix the prestressed tendons through the anchor devices of the anchoring system to establish the same initial prestressed state as the actual project inside the test body, simulating the initial working conditions of the prestressed structure in the actual project;

[0075] S1-4, Construction of the reaction system:

[0076] Construction of a reaction system based on the upper spatial structure: If there is a usable spatial structure above the underground space (such as a top load-bearing beam or steel frame), a force transmission support is installed above the prestressed slab rib beam test body. The force transmission support must be parallel to the test body plate surface and have uniform contact. Then, a reaction beam is installed above the force transmission support. The two ends of the reaction beam are reliably connected to the upper spatial structure of the underground space, forming a force transmission path of "upper spatial structure - reaction beam - force transmission support - test body", ensuring stable transmission of reaction force during loading.

[0077] Construction of the reaction system based on the sidewall and bottom plate: If there is no available space structure above the underground space, ground anchors or rigid columns are used as reaction support components; the ground anchors are inserted into the pre-set holes in the sidewall and bottom plate of the underground space, or rigid columns are installed between the sidewall and bottom plate to ensure that the anchoring force of the ground anchors and the bearing capacity of the rigid columns meet the loading reaction force requirements; then the reaction frame is fixedly connected to the ground anchors or rigid columns so that the reaction frame and the test body form a corresponding loading position, and a stable reaction system of "sidewall / bottom plate-ground anchor / rigid column-reaction frame-test body" is constructed to provide continuous and stable reaction support for subsequent hydraulic jack staged loading.

[0078] In this embodiment, step S2 aims to establish a measurement system capable of capturing the key structural responses of the prestressed slab rib beam in real time by accurately locating the critical stress-bearing parts of the test specimen, matching and adapting sensors, standardizing installation and fixation, and constructing a stable data transmission network. This provides an accurate data source for monitoring stress, deformation, and prestress changes during subsequent graded loading processes, ensuring the validity and reliability of the test data. The specific steps for setting up the measurement system in step S2 include:

[0079] S2-1, Key Part Markings:

[0080] Analysis of stress characteristics in conjunction with drawings: First, obtain the design drawings of the prestressed slab-ribbed beam test body to clarify the dimensional parameters and connection relationships of the slab, ribbed beam, and prestressing tendons; then, combine with structural mechanics analysis to determine the criticality of stress in each part. For example, the mid-span of the slab and the mid-span of the ribbed beam are areas of concentrated bending moment, the slab support and the ribbed beam support are areas of critical shear force, the anchorage zone of the prestressing tendons is the core area of ​​prestress transfer, and the curved section of the prestressing tendons is an area of ​​complex stress changes. The structural response of these parts directly reflects the overall performance of the test body.

[0081] Precise marking on the test specimen surface: Based on the above analysis results, high-precision measuring tools (such as total station and steel tape measure) are used to mark the specific locations of the slab mid-span, slab support, rib beam mid-span, rib beam support, prestressed tendon anchorage zone, and prestressed tendon curve segment on the test specimen surface; the markings must be clear and not easily detached to ensure that the subsequent sensor installation can accurately correspond to the key parts and avoid data acquisition distortion due to positional deviation.

[0082] S2-2, Sensor Selection and Preparation:

[0083] Sensor type matching and selection: Determine the sensor type based on the measurement requirements of each key component. For stress change measurement, select strain sensors at locations such as the mid-span of the slab, the mid-span of the rib beam, and the supports. For deformation measurement, select displacement sensors at displacement-sensitive locations such as the mid-span of the slab and the mid-span of the rib beam. For prestressed tendon stress state monitoring, select prestressed tendon anchorage zones and curved sections. The range and accuracy of the selected sensors must match the expected measurement range and test requirements to ensure complete capture of structural response data.

[0084] Sensor calibration and initialization: Connect the selected sensor to the standard calibration equipment, and adjust the sensor output by applying a known standard signal (such as standard strain value, standard displacement) to control the sensor measurement error within the allowable range of the test, thus completing the calibration operation; then initialize the calibrated sensor, for example, adjust the initial output value of the strain sensor to zero, and align the initial measurement reference of the displacement sensor with the initial state of the test body to ensure that the sensor is in the initial state of normal operation.

[0085] S2-3. Sensor Installation and Fixing:

[0086] Installation method selection: Select the installation method according to the sensor type and installation location characteristics. For strain sensors that need to be attached to the surface of the test body, use a structural adhesive to firmly bond them to the marked key parts. Before bonding, the surface of the test body needs to be polished and cleaned to remove impurities and dust to ensure a firm bond. For displacement sensors that need to be fixed in a specific position, use mechanical fixing methods (such as bolted brackets) to install them on the surface of the test body or surrounding fixed components to ensure precise contact between the sensor measuring end and the measuring point of the test body. For sensors that need to monitor internal prestress, if the test body has pre-drilled mounting holes during casting, directly place the sensor in the preset position and fix it to avoid the sensor from loosening.

[0087] Post-installation status check: After the sensor is installed, manually touch the sensor and connecting wires to check for any looseness; at the same time, observe the contact status between the sensor and the test object to ensure that there are no gaps or offsets, and that the installation of the sensor does not change the original structural shape and force path of the key parts of the test object, so as to avoid affecting the normal force of the test object due to improper installation.

[0088] S2-4. Data acquisition system connection:

[0089] Measurement network setup: Connect all installed sensors one by one to the corresponding interface of the data acquisition device using dedicated signal cables, and record them according to the sensor number and acquisition channel number to form a complete measurement network; during the connection process, the signal cables should be tidied up to avoid signal interference or line damage caused by the cables crossing and tangling.

[0090] System debugging and verification: Start the data acquisition equipment and supporting software, and debug the measurement network; first check the communication status of each sensor and the acquisition equipment to ensure that there is no signal interruption or loss; then apply a small external interference (such as lightly pressing a local part of the test body) and observe whether the corresponding sensor can output change data in real time to verify the real-time performance of data transmission; finally, compare the measurement data of different sensors at the same location (if there is redundant installation) to ensure data consistency, thereby verifying the stability and accuracy of data transmission. After successful debugging, keep the data acquisition system in a standby state.

[0091] In this embodiment, step S3 simulates the load-bearing process of a large-span prestressed slab rib beam in an actual engineering project. By applying loads in stages and coordinating with load monitoring, the deformation response of the structure at different load stages is gradually captured, avoiding sudden structural failure due to a single loading and loss of key data. This ensures accurate acquisition of the complete mechanical behavior of the structure from the elastic stage to the near-failure stage. The specific steps of applying the graded load in step S3 include the following:

[0092] S3-1. Loading scheme determined:

[0093] Load-related parameter analysis: First, obtain the design load of the prestressed slab-ribbed beam test specimen. This design load must be consistent with the load that the slab-ribbed beam needs to bear in the actual underground space project. At the same time, clarify the expected performance indicators of the test specimen, including the design bearing capacity and the maximum allowable deformation. Based on these parameters, combined with the stress characteristics of the concrete structure (such as the difference in load response in the elastic stage and the elastoplastic stage), determine the load level of graded loading. Usually, the maximum design load is divided into several equal or unequal load levels. The load level in the early stage can be appropriately larger, and the load level needs to be reduced when approaching the maximum design load in order to accurately capture the response near failure.

[0094] Holding time and stability criteria setting: Based on the creep characteristics of concrete, the holding time corresponding to each load level is set to ensure that the structure has enough time to complete instantaneous deformation and creep deformation; at the same time, the deformation stability criteria are defined, that is, when the deformation rate of the test body is lower than the preset threshold for a continuous period of time (such as the deformation amount per hour does not exceed 0.1 mm), the structure is judged to be deformed and stable. This threshold needs to be determined in combination with the test accuracy requirements and the structure type.

[0095] S3-2, Initial load application:

[0096] Loading equipment debugging and positioning: Check the connection status of the reaction system and hydraulic jacks to ensure that the jacks are in uniform contact with the surface of the prestressed slab rib beam test body. The jacks should be positioned to correspond to the critical stress areas of the slab rib beam (such as the slab surface above the rib beam) to avoid localized concentrated stress that could lead to premature damage to the slab surface. Start the jack control system and adjust the loading accuracy of the jacks to ensure that the load output is consistent with the set value.

[0097] First-level load application and data recording: The first-level load is applied to the test plate surface using hydraulic jacks. The loading process should be slow and uniform to avoid sudden load changes that could impact the structure. When the jack reading reaches the first-level load set value, loading is stopped, and the initial loading data is recorded, including the loading time, jack load value, and initial deformation data of the test plate collected by the measurement system (such as the initial displacement at the mid-span of the plate and the mid-span of the rib beam).

[0098] S3-3, Load Holding and Deformation Monitoring:

[0099] Real-time monitoring during load holding: After entering the load holding stage, keep the jack load stable and prevent load fluctuations; at the same time, start the measurement system to collect deformation data of key parts of the test body in real time, focusing on monitoring the displacement changes at the mid-span of the plate and the mid-span of the rib beam, and obtain the deformation value at fixed intervals (e.g., 5 minutes) through displacement sensors to form deformation time series data;

[0100] Deformation stability judgment: The deformation rate, i.e. the deformation increment per unit time, is calculated based on the collected deformation data. When the deformation rate is lower than the preset deformation stability threshold for multiple consecutive monitoring cycles (e.g., 6 consecutive cycles, each cycle 5 minutes), the test body is judged to be stable under this load level. If the deformation rate is always higher than the threshold, the holding time needs to be extended until the deformation meets the stability standard.

[0101] S3-4, Subsequent Load Application:

[0102] Load adjustment and application: After confirming that the structural deformation is stable under the previous load, analyze the deformation results corresponding to the previous load; if the deformation is within the expected range and there are no abnormalities (such as no cracks), apply the next load according to the preset load level; if the deformation under the previous load is too large but does not exceed the safety range, the increment of the next load can be appropriately reduced to avoid the structure entering the elastic-plastic stage too early; when applying the next load, it is still necessary to operate slowly and uniformly until the set value of the load level is reached.

[0103] Cyclic monitoring process: After the next level of load is applied, the load holding and deformation monitoring process is repeated, that is, the load is kept stable, deformation data is collected in real time, the deformation rate is calculated and the deformation is judged to be stable, until the structural deformation under this level of load meets the stability requirements, and then the next level of load application process is entered, and so on in a cyclical manner.

[0104] S3-5, Load Termination Judgment:

[0105] Determining the maximum design load: When the load is continuously applied and the jack load value reaches the preset maximum design load, the loading is stopped regardless of whether the test body shows any abnormalities. The final load value, deformation data of key parts of the test body, and whether there are cracks or excessive deformation in the structure are recorded at this time.

[0106] Judgment of signs of failure: During the loading process, closely observe the appearance and measurement data changes of the test specimen; if signs of failure appear, such as obvious through cracks on the plate surface, excessive bending deformation of the rib beams, loosening or displacement of the prestressed tendon anchorage zone, or a sudden and sharp increase in deformation data, loading must be stopped immediately to avoid complete failure of the test specimen; at the same time, record in detail the final load state (final load reading of the jack), deformation data (maximum deformation and location of occurrence), and the specific manifestation and location of the signs of failure.

[0107] In this embodiment, step S4 aims to synchronously and accurately capture the structural response data of the prestressed slab rib beam test specimen during the graded loading process. By ensuring the real-time nature, completeness, and effectiveness of data acquisition, it provides high-quality raw data support for subsequent test data processing and structural performance evaluation, ensuring that the data accurately reflects the changes in the mechanical state of the test specimen at different load stages. The real-time data monitoring and acquisition in step S4 specifically includes the following steps:

[0108] S4-1. Data Acquisition System Initialization:

[0109] System startup and equipment check: Before the staged load test begins, start the data acquisition equipment and its supporting software system, and check whether the power supply between the acquisition equipment and each sensor is stable and whether the hardware connection is secure, to ensure that there are no equipment failures or loose wiring problems.

[0110] Parameter setting and configuration: Based on the test monitoring requirements and sensor type, set the sampling frequency of all measurement sensors. For example, strain sensors need to be set to a higher sampling frequency (e.g., 10 times per second) to adapt to the structural deformation rate, while displacement sensors can be set to a moderate sampling frequency (e.g., once every 30 seconds) based on the deformation stabilization period. At the same time, set the sensor range to ensure that the range covers the expected maximum strain value, maximum displacement, and prestress variation range of the test body, avoiding data distortion caused by exceeding the range. Finally, configure data storage parameters, including storage path, file format (e.g., CSV format for easy subsequent processing), and data backup frequency to ensure that the collected data can be safely stored.

[0111] S4-2, Synchronous Triggered Acquisition:

[0112] Trigger signal association: The loading control system of the hydraulic jack is associated with the data acquisition system through signal lines to establish a linkage mechanism between loading commands and acquisition triggers, ensuring that a trigger signal can be sent to the data acquisition system synchronously the moment the loading command for each load level is issued;

[0113] Synchronous data acquisition and startup: When the loading control system issues the command "start applying a certain level of load", the trigger signal is synchronously transmitted to the data acquisition system. The system immediately starts the data acquisition operation of all strain sensors, displacement sensors and prestress monitoring sensors, so as to achieve precise time correspondence between "load application and data acquisition" and avoid the mismatch between load and structural response data due to time difference.

[0114] S4-3, Real-time Data Stream Monitoring:

[0115] Data flow channel establishment: During the data acquisition process, a real-time data flow channel from each sensor to the data acquisition device is constructed through the acquisition software to ensure that the electrical signals output by the sensors (corresponding to strain, displacement, and prestress physical quantities) can be transmitted to the acquisition device in real time and complete analog-to-digital conversion.

[0116] Real-time data display and monitoring: The acquisition software displays the converted strain data, displacement data and prestress data in the form of waveform graphs or numerical lists in real time. Staff can monitor the data change trends in real time, such as whether the strain waveform is stable (without abnormal jumps) and whether the displacement value changes reasonably with the increase of load. If abnormal data fluctuations are found, it can be preliminarily judged whether there is a problem with the sensor or the connection line.

[0117] S4-4, Data Quality and Integrity Verification:

[0118] Data validity assessment: Based on the real-time monitored data stream, the system automatically screens the data validity using built-in rules in the acquisition software. For example, when strain data exceeds the sensor's range, displacement data shows negative values ​​(inconsistent with the preset deformation direction), or prestress data shows no change, the system automatically marks this part of the data as abnormal data. At the same time, staff regularly manually check the data to supplement any abnormalities not identified by the software (such as periodic fluctuations in data that may be caused by external interference).

[0119] Anomaly Handling and Supplementary Testing: If an abnormal signal or data loss is detected, first check the installation status, wiring, and power supply of the corresponding sensor. After ruling out hardware failures, restart the data acquisition of the sensor during the stable load phase of the current load level for supplementary testing. If the sensor is damaged, replace it with a spare sensor, recalibrate and install it before supplementary testing to ensure that the key data under each load level are complete.

[0120] S4-5, Generation and storage of hierarchical datasets:

[0121] Data classification and integration: After the load holding phase of each load level is completed, the acquisition system automatically classifies the data collected by all sensors in this phase according to the load level. The data under the same load level are further classified and organized according to the time sequence (from the start of loading to the end of the load holding phase) and the sensor location (mid-span of slab, slab support, mid-span of rib beam, rib beam support, prestressed tendon anchorage zone, prestressed tendon curve segment) to form a structured data table.

[0122] Dataset storage and backup: The completed structural response datasets for the corresponding load levels are stored on the local hard drive in the specified file format, and simultaneously transferred to a backup storage device via the network. The storage file name must include the load level number, acquisition date, and sensor type information (e.g., "Load Level 3_202X0X0X_Strain Displacement Data") to facilitate quick retrieval in subsequent step S5.

[0123] In this embodiment, step S5 involves systematically processing the raw structural response data collected during the graded loading process, deeply analyzing the mechanical behavior characteristics of the prestressed slab rib beam test specimen, accurately identifying the structural failure mode, and ultimately comprehensively evaluating its overall structural performance. This provides a scientific basis for the engineering design, construction, and safe application of large-span prestressed slab rib beams in underground spaces. The specific steps of test data processing and performance evaluation in step S5 include the following:

[0124] S5-1, Structural Response Data Preprocessing:

[0125] Raw data filtering: For the raw strain data, displacement data and prestress data collected in step S4, a filtering algorithm (such as low-pass filtering) is used to remove high-frequency noise (such as irregular data fluctuations caused by external vibration and electromagnetic interference) from the data, retain the effective signals related to the actual stress and deformation of the structure, and make the data curve smoother and more in line with the actual response law of the structure.

[0126] Outlier removal: The filtered dataset is screened using statistical analysis methods (such as the 3σ criterion) to identify and remove outlier data that exceeds reasonable limits (such as sudden data caused by instantaneous sensor failure or unreasonable values ​​that exceed the physical performance limits of materials). After filtering and outlier removal, a clean, continuous strain data sequence, displacement data sequence, and prestress data sequence that can truly reflect the structural state are obtained.

[0127] S5-2, Establishing the load-deformation relationship:

[0128] Data Matching: The clean displacement data sequence obtained in step S5-1 (focusing on extracting displacement data in the mid-span of the slab and the mid-span of the rib beam) is matched with the load data of the graded loading in step S3 in terms of time and load level to ensure that each set of displacement data can be accurately associated with the corresponding applied load value.

[0129] Load-deformation curve plotting: Based on the matched load and displacement data, plot the load-deformation curves of the prestressed slab-ribbed beam test body with load values ​​on the x-axis and displacement values ​​on the y-axis, including the load-displacement curve at mid-span of the slab and the load-displacement curve at mid-span of the ribbed beam; the curves should clearly show the displacement change trend at different load stages (elastic stage, elastoplastic stage) and intuitively reflect the deformation characteristics of the structure under load.

[0130] S5-3, Stiffness Evolution Analysis:

[0131] Equivalent stiffness calculation: Based on the load-deformation curve drawn in step S5-2, calculate the equivalent stiffness under each load level; the equivalent stiffness is calculated according to the formula K=ΔP / Δδ (where K is the equivalent stiffness under a certain load level, ΔP is the difference between the current load level and the previous load level, and Δδ is the displacement increment at the mid-span of the slab or the mid-span of the rib beam under the corresponding load increment); the equivalent stiffness corresponding to each load level is calculated sequentially using this formula to obtain the stiffness data sequence;

[0132] Stiffness evolution law analysis: Plot the stiffness evolution curve with load level as the abscissa and equivalent stiffness as the ordinate to analyze the change law of stiffness with increasing load. For example, in the elastic stage, the stiffness remains stable or fluctuates slightly; after entering the elastoplastic stage, the stiffness gradually decreases with increasing load (due to the appearance of microcracks in the structure, the bearing capacity gradually weakens). The critical load point at which the structural stiffness begins to decrease can be identified through the curve characteristics, and the transition stage of the structure from elastic to elastoplastic can be judged.

[0133] S5-4. Analysis of Prestressing Effect:

[0134] Extraction of prestressed tendon stress variation: From the clean prestressed data sequence obtained in step S5-1, extract the stress values ​​of prestressed tendons (focusing on the anchorage zone and curved sections) under different load levels to form prestressed tendon stress-load relationship data;

[0135] Prestress contribution assessment: Analyze the trend of prestressed tendon stress with increasing load. For example, in the initial loading stage, the prestressed tendon stress increases linearly with the load, offsetting part of the tensile stress generated by the external load. Compare with the conventional stress characteristics of non-prestressed structures (such as deformation and stress distribution under the same load) to assess the effect of prestressing on improving structural stiffness (such as smaller displacement increment and higher stiffness of prestressed structures under the same load increment) and enhancing bearing capacity (such as prestressed structures being able to withstand higher loads without failure).

[0136] S5-5, Stress redistribution process analysis:

[0137] Stress calculation of key components: Based on the clean strain data sequence obtained in step S5-1, and combined with the material parameters (such as the elastic modulus of concrete and the elastic modulus of steel) and the cross-sectional geometric parameters (such as the slab thickness and the cross-sectional dimensions of the rib beam) of the prestressed slab rib beam test body, the stress calculation formula of material mechanics (such as σ=Eε, where σ is stress, E is the elastic modulus of material, and ε is strain) is used to calculate the stress values ​​of key components such as the mid-span of the slab, the slab support, the mid-span of the rib beam, and the rib beam support under various load levels.

[0138] Stress redistribution pattern analysis: By comparing the stress distribution data of key parts under various load levels, the stress redistribution process from the plate to the rib beams during loading is analyzed. For example, in the early stage of loading, the plate bears more stress, while the rib beams bear less stress. As the load increases, cracks gradually appear in the plate, and the stress gradually shifts to the rib beams with greater stiffness. The stress ratio of the rib beams continuously increases. Through this process, the changes in the force transmission path inside the structure can be clearly identified.

[0139] S5-6, Damage Mode Recognition:

[0140] Multi-dimensional data correlation analysis: The results of stiffness evolution analysis in step S5-3 (such as load points where stiffness suddenly drops sharply), the results of prestress effect analysis in step S5-4 (such as the state where the stress of prestressing tendons stops increasing or suddenly drops), and the results of stress redistribution process analysis in step S5-5 (such as local stress concentration phenomena) are correlated with the structural appearance changes observed during the test (such as the location of cracks and the crack development pattern).

[0141] Determination of failure initiation point and mode: Through correlation analysis, the failure initiation point of the structure is identified (i.e., the load level at which the stiffness first drops significantly, local stress concentration is obvious, and initial cracks appear); based on the structural response characteristics and appearance after the failure initiation point, the failure mode is determined. For example, if the cracks mainly appear in the middle of the slab span and the middle of the rib beam span and develop along the tensile direction, it is determined to be bending failure; if the cracks appear near the support and develop obliquely, it is determined to be shear failure.

[0142] S5-7 Structural Performance Evaluation:

[0143] Sub-item performance evaluation: Based on the failure mode identification results of step S5-6, combined with the analysis data of steps S5-3 (stiffness evolution), S5-4 (prestress effect), and S5-5 (stress redistribution), the sub-item performance of the prestressed slab-rib beam test specimen is evaluated respectively; when evaluating the bearing capacity, the load corresponding to the failure initiation point or the design maximum load is used as the basis to determine whether the structure meets the design bearing capacity requirements; when evaluating the deformation capacity, the maximum displacement before failure is compared with the allowable displacement to determine whether the deformation of the structure is within the safe range; when evaluating the safety reserve, the ratio of the failure load to the design load is calculated, and the larger the ratio, the higher the safety reserve;

[0144] Overall performance assessment: Based on the comprehensive performance evaluation results of each component and the actual usage requirements of the structure in underground space engineering (such as long-term load-bearing stability and deformation resistance), a final assessment of the overall structural performance of the prestressed slab rib beam test specimen is made. This clarifies whether the structure is suitable for safe application in large-span underground space scenarios and provides directions for improvement in engineering optimization design (such as adjusting the configuration of prestressed tendons and optimizing cross-sectional dimensions).

[0145] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for surcharge testing of large-span full-scale prestressed slab rib beams in underground spaces, characterized in that: Includes the following steps: S1. Test System Construction: Within the underground space, a full-scale prestressed slab-ribbed beam test body is constructed based on the actual engineering structure and geological conditions. The prestressed slab-ribbed beam test body includes a slab, ribbed beams, prestressing tendons, and an anchoring system. A reaction system is constructed around the prestressed slab-ribbed beam test body. The reaction system provides reaction force through a spatial structure set above the test body, or through rigid reaction force members anchored to the side walls and bottom slab of the underground space. S2. Measurement system setup: Measurement sensors are set up at key locations of the prestressed slab rib beam test body. Key locations include the mid-span of the slab, the slab support, the mid-span of the rib beam, the rib beam support, the prestressing tendon anchorage zone, and the prestressing tendon curve segment. S3. Graded loading: Through the reaction system, hydraulic jacks are used to apply graded loading to the surface of the prestressed slab rib beam test body. After each load is applied, the load is held until the structural deformation stabilizes. S4. Real-time data monitoring and acquisition: During the staged loading process, data from all measurement sensors are acquired synchronously to obtain structural response data; S5. Test Data Processing and Performance Evaluation: Based on structural response data, the stiffness evolution, prestressing effect, stress redistribution process and failure mode of the prestressed slab rib beam test specimens are analyzed to evaluate the structural performance.

2. The method for surcharge testing of large-span full-scale prestressed slab rib beams in underground spaces according to claim 1, characterized in that: The construction of the experimental system in step S1 specifically includes the following steps: S1-1. Foundation treatment and foundation construction: Based on the actual engineering geological conditions, the foundation of the underground space test area is compacted and leveled, and then the concrete foundation of the prestressed slab rib beam test body is constructed according to the design drawings. S1-2, Construction of full-scale test body: On the completed foundation, the reinforcement binding and formwork support of the rib beams are carried out in sequence, the bottom reinforcement of the slab is laid, the prestressing tendon duct is reserved, and then the overall concrete is poured and cured to form a full-scale prestressed slab rib beam test body that is the same as the actual structure of the project. S1-3. Installation of the prestressing system: After the concrete of the test body reaches the design strength, the prestressing tendons are inserted and tensioned and anchored using the anchoring system to establish the initial prestress. S1-4. Construction of the reaction system: Select the reaction supply method according to the underground space conditions. When the upper space structure is used, install the force transmission support and reaction beam on the plate-rib beam test body. When the side wall and bottom plate are used, anchor the reaction frame to the side wall and bottom plate of the underground space through ground anchors or rigid columns to form a complete loading reaction system.

3. The method for surcharge testing of large-span full-scale prestressed slab rib beams in underground spaces according to claim 1, characterized in that: The specific steps for setting up the measurement system in step S2 include the following steps: S2-1. Key component identification: Based on the design drawings and structural stress characteristics of the prestressed slab rib beam test body, the specific locations of key components are accurately identified on the surface of the test body. Key components include the mid-span of the slab, the slab support, the mid-span of the rib beam, the rib beam support, the prestressed tendon anchorage zone, and the prestressed tendon curved segment. S2-2, Sensor Selection and Preparation: Based on the stress and deformation measurement requirements of key parts, select the corresponding strain sensors, displacement sensors and prestress monitoring sensors, and complete the calibration and initialization settings of the sensors. S2-3. Sensor Installation and Fixing: At the marked key locations, use adhesive or mechanical fixing methods to install the sensor on the surface or inside the test body at the preset position, ensuring that the sensor is in close contact with the structure and does not affect the stress on the structure. S2-4. Data Acquisition System Connection: Connect the installed sensors to the data acquisition equipment via signal lines to form a complete measurement network, and perform system debugging to verify the stability and accuracy of data transmission.

4. The method for surcharge testing of large-span full-scale prestressed slab rib beams in underground spaces according to claim 1, characterized in that: The specific steps involved in applying the graded loading in step S3 are as follows: S3-1. Determination of loading scheme: Based on the design load and expected performance of the prestressed slab rib beam test body, determine the load level, holding time and deformation stability standard of graded loading. S3-2, Initial Load Application: Using the reaction system, hydraulic jacks are used to apply the first load to the surface of the prestressed slab rib beam test body, and the initial loading data is recorded. S3-3, Load Holding and Deformation Monitoring: After each load level is applied, a load holding operation is performed, and the deformation data of the test body is monitored in real time using a measurement system until the deformation rate is lower than the preset threshold, at which point the structure is determined to be stable. S3-4. Subsequent load application: After the structural deformation stabilizes, the next load is applied based on the deformation results of the previous load, and the load holding and deformation monitoring process is repeated. S3-5. Loading Termination Judgment: When the load is applied to the maximum design load or the test specimen shows signs of failure, stop loading and record the final load state and deformation data.

5. The method for surcharge testing of large-span full-scale prestressed slab rib beams in underground spaces according to claim 1, characterized in that: The real-time data monitoring and collection in step S4 specifically includes the following steps: S4-1. Data Acquisition System Initialization: Start and configure the data acquisition system before the start of graded loading, and set the sampling frequency, range and data storage parameters of all measurement sensors. S4-2, Synchronous Trigger Acquisition: At the same time as each load loading command is issued, a synchronous trigger signal is sent to the data acquisition system to start synchronous acquisition of data from all measuring sensors; S4-3 Real-time data stream monitoring: During the acquisition process, a real-time data stream channel is established from the sensor to the data acquisition device to display and monitor the acquired strain, displacement and prestress data in real time. S4-4 Data Quality and Integrity Verification: Based on the real-time monitored data stream, the validity of the data is judged, signal anomalies or data loss are marked, and supplementary measurements or sensor status adjustments are performed during the load stabilization phase. S4-5. Generation and storage of hierarchical datasets: After the end of each load holding phase, all sensor data collected in this phase are classified and integrated according to load level, time series and sensor location to generate and store the structural response dataset corresponding to that load level.

6. The method for surcharge testing of large-span full-scale prestressed slab rib beams in underground spaces according to claim 1, characterized in that: The experimental data processing and performance evaluation in step S5 specifically includes the following steps: S5-1, Structural response data preprocessing: Filter and remove outliers from the raw structural response data collected in step S4 to obtain a clean strain, displacement and prestress data sequence. S5-2, Load-deformation relationship establishment: Based on the clean data sequence obtained in S5-1, the load-deformation curves of the prestressed slab rib beam test body during the graded loading process are plotted, including the load-displacement relationship between the mid-span of the slab and the mid-span of the rib beam. S5-3, Stiffness Evolution Analysis: Calculate the equivalent stiffness under each load level based on the load-deformation curve, and analyze the evolution law of stiffness with increasing load. S5-4. Prestressing Effect Analysis: Based on the analysis of clean prestressing data sequence, the stress change of prestressing tendons during surcharge is analyzed to evaluate the contribution of prestressing to the structural stiffness and bearing capacity. S5-5, Stress Redistribution Process Analysis: The stress distribution of key parts is calculated using clean strain data sequences, and the stress redistribution process from the plate to the rib beam during loading is analyzed. S5-6. Failure Mode Identification: Combining the results of stiffness evolution analysis, prestress effect analysis, and stress redistribution process analysis, identify the failure initiation point and failure mode of the test specimen. S5-7 Structural Performance Assessment: Based on the failure mode identification results and the analysis results of S5-3, S5-4, and S5-5, the overall structural performance of the prestressed slab rib beam test specimen is comprehensively evaluated. The overall structural performance of the prestressed slab rib beam test specimen includes bearing capacity, deformation capacity, and safety reserve.

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