Construction method of large cantilever hollow truss auditorium structure

Abstract

This invention relates to a construction method for a large cantilevered truss auditorium structure, comprising the following construction steps: S1: detailed design; S2: pre-reservation and embedding of substructure; S3: installation of the first-stage temporary substructure support; S4: erection of formwork support frame and cantilevered scaffolding; S5: construction of the lower stepped layer and suspended layer; S6: installation of the second-stage support; S7: construction of the stepped layer, upper stepped layer and roof layer layer by layer; S8: unloading and dismantling. This invention has advantages such as a clear force system, progressively increasing bearing capacity, precise control of elevation and unloading, integration of construction and decoration, and information-based monitoring. It effectively solves the problems of large load, difficult monitoring, and lack of working surface in the construction of large cantilevered structures, and is safe and reliable.

Description

Technical Field

[0001] This invention belongs to the field of building construction technology, and specifically relates to a construction method for a large cantilevered hollow truss auditorium structure. Background Technology

[0002] In large public buildings such as auditoriums, stadiums, and theaters, large cantilevered open truss structures are widely used due to their aesthetic appeal, high space utilization, and ability to create large, column-free spaces. However, the construction of such structures presents significant technical challenges.

[0003] First, before the cantilevered open truss forms a complete load-bearing system, the truss itself cannot bear the structural weight. The weight of all beams and columns in the upper floors (including suspended floors, stepped floors, and roof floors) must be borne by the temporary support platform below. Due to the large number of floors and the enormous self-weight of the structure, the temporary support platform bears a huge load, and the load application process is difficult to monitor precisely, introducing uncontrollable factors to the safety of the steel platform and posing serious safety hazards.

[0004] Secondly, the large cantilever structure lacks reliable ground support, rendering conventional ground-based scaffolding unusable for safety during construction. Furthermore, the subsequent facade and base exterior finishing work presents a challenge due to the lack of operational platforms; traditional methods require the erection of separate high-altitude work platforms, increasing construction costs and extending the construction period.

[0005] In existing technologies, heavy-duty steel platforms are often used in conjunction with large jacks for support and unloading. However, jacks are expensive, prone to damage when placed on top of temporary columns for extended periods, and difficult to replace. While sandboxes offer unloading capabilities, precise elevation adjustment is inconvenient, failing to meet the high-precision construction requirements of large cantilever structures. Furthermore, traditional construction methods lack phased stress reinforcement design, making it difficult to meet the load-bearing capacity requirements of simultaneous construction on multiple floors.

[0006] Therefore, there is an urgent need for a construction method for large cantilevered open truss auditorium structures that can achieve precise load control, a clear force system, and integrated construction and decoration. Summary of the Invention

[0007] The purpose of this invention is to provide a construction method for a large cantilevered truss auditorium structure that is safe and reliable, has clear stress distribution, precise control over elevation and unloading processes, and integrates construction protection and exterior decoration functions.

[0008] The technical solution of this invention is a construction method for a large cantilevered open truss auditorium structure, comprising the following construction steps: S1: Detailed Design Determine the construction sequence based on the site structure, and conduct detailed design of the lower support and segmented design of the steel in the steel-concrete composite column. S2: Pre-reserved and embedded parts in the substructure The connection points of the first temporary diagonal brace, the platform main beam, and the lower support are pre-embedded in the substructure; S3: Install the first phase of temporary lower support The first temporary diagonal brace, the platform main beam, and the lower support are installed at the corresponding connection point of the lower structure. A steel platform is set on the platform main beam, and temporary columns are installed near the connection point of the platform main beam and the lower support. S4: Erect formwork support frames and cantilevered scaffolding A formwork support frame is erected on the steel platform, and a cantilevered scaffold is erected on its outer side; S5: Construction of the lower stepped floor and suspended floor Install an elevation adjuster on the top of the temporary column, adjust it to the required height for support, erect the formwork, and pour the floor concrete. S6: Second-stage support installation After the concrete of the lower stepped layer and the suspended layer reaches the required strength and the formwork is removed, the second temporary diagonal brace and the upper tie rod are installed on the concrete structure. S7: Construction steps, upper step layer and roof layer; S8: Unloading and removal; After the roof concrete pouring is completed, the formwork and formwork support frame are removed from bottom to top; after removal, the formwork is unloaded using the elevation adjuster; after unloading, the temporary columns, upper tie rods, second temporary supports, cantilever scaffolding, platform distribution beams, first temporary supports, lower supports, and platform main beams are removed in sequence.

[0009] As a preferred option, step S3 is refined as follows: S3.1 Install the first temporary diagonal brace: After the concrete of the lower structure is poured, the first temporary diagonal brace is installed at the corresponding connection point. The pre-embedded first temporary diagonal brace is used as a tension member and is fixedly connected to the concrete structure by pre-embedded bolts. The lower end of the first temporary diagonal brace is fixed by a through-wall pre-embedded bolt assembly. S3.2 Install the main beam and lower support of the platform: Fix the lower support to the bottom of the main beam of the platform and connect them into an integral hoisting unit, and then hoist the whole unit into place; The main beam of the platform, as a tension member, is fixedly connected to the concrete structure with pre-embedded bolts; The lower support, as a compression member, is fixedly connected to the concrete structure with steel plate pre-embedded parts for anchoring steel bars by perforation and plug welding. S3.3 Laying Platform Distribution Beams: Platform distribution beams are laid on the main beam of the platform to form the steel platform. The spacing of the platform distribution beams is consistent with the spacing of the uprights of the formwork support frame. S3.4 Install temporary columns: Install temporary columns near the intersection of the platform main beam and the lower support.

[0010] As a preferred option, when the cantilever span increases or the construction load increases, several small supports are added between the lower support and the main beam of the platform to form a small truss structure, and small supports are added between adjacent lower supports and between adjacent main beams of the platform to connect the steel platform laterally into a whole.

[0011] Preferably, the through-wall embedded bolt assembly includes: a steel sleeve embedded in the concrete column, a steel back plate and a component end plate attached to both sides of the concrete column, and an anchor bolt; the component end plate is fixed to the bottom of the first temporary diagonal brace, and the anchor bolt passes through the steel back plate, the steel sleeve and the component end plate in sequence and is locked by a nut, and a steel washer is provided between the head of the anchor bolt and the steel back plate, and between the nut and the component end plate.

[0012] Preferably, in step S4, cantilevered scaffolding I-beams are installed at the ends and sides of the main beam of the platform, and the cross-section of the cantilevered scaffolding I-beams is smaller than that of the main beam of the platform; transverse I-beam distribution beams are installed on the cantilevered scaffolding I-beams, and the cantilevered scaffolding is erected on the transverse I-beam distribution beams, with the cantilevered scaffolding connected to the platform distribution beams and the main beam of the platform.

[0013] As a preferred option, step S5 is refined as follows: S5.1 Install supporting steel columns: Install supporting steel columns on both sides of the auditorium, with the connection nodes of the supporting steel columns being 0.5-1m higher than the upper surface of the steps; S5.2 Structural column construction: Construct the structural columns under the lower stepped floor and suspended floor, and erect formwork support frames simultaneously; S5.3 Install elevation adjuster: Install elevation adjuster on top of the temporary column. The elevation adjuster includes two right-angled triangular blocks with their inclined surfaces touching each other, and a through screw rod passing through the middle of the two right-angled triangular blocks. The relative position of the two triangular blocks is adjusted by rotating the through screw rod to change the elevation. Adjust it to the height required for support and support the template. S5.4 Install the steel columns under the suspended columns and the steel beams of the suspension beams: Install multiple steel columns under the suspended columns at intervals along the transverse direction of the auditorium. The position of the steel columns under the suspended columns corresponds to the plane position of the temporary columns. The top of the steel columns under the suspended columns after installation is 0.5-1m higher than the upper surface of the suspension layer. S5.5 Setting tie column steel column connection points: Install anchor bolts for tie column steel columns on the upper surface of both ends of the main beam under the steps; S5.6 Setting diagonal brace connection points: Reserve steel bar joints for diagonal braces on both sides of the horizontal axis of the auditorium; S5.7 Pouring floor concrete: After completing the binding of beam and slab reinforcement, pour floor concrete to complete the construction of the lower stepped floor and suspended floor.

[0014] Preferably, in step S6, second temporary diagonal braces and upper tie rods are installed on both sides and in the middle area of ​​the auditorium, and the lower end of the second temporary diagonal brace is fixed by a through-wall pre-embedded bolt assembly. The installation method of the second temporary diagonal brace and the upper tie rod is as follows: For the two sides of the auditorium, the lower end of the second temporary diagonal brace is connected to the tie column and the upper end is connected to the support column, and the upper end of the upper tie rod is connected to the support column and the lower end is connected to the platform main beam; For the middle area of ​​the auditorium, the two ends of the second temporary diagonal brace are connected to the adjacent lower column respectively, and the upper end of the upper tie rod is connected to the lower column and the lower end is connected to the platform main beam.

[0015] As a preferred option, step S7 is refined as follows: S7.1 Construction of the steps and upper steps: Erect cantilever scaffolding and tie it to the lower suspended beam structure; after the concrete of the suspended layer reaches the strength, install the steel columns on the suspended columns to the roof; erect the formwork support frame on the suspended layer, tie the beam and slab reinforcement of the steps and upper steps, and pour concrete to complete the structural construction of the steps and upper steps. S7.2 Roofing construction: Install steel columns on the support columns, complete the installation and alignment of the roof steel beams between the support columns and the hanging columns, and simultaneously complete the installation and alignment of the upper hanging beam steel beams; install tie columns on both sides of the lower step to the roof, and complete the installation and alignment of the roof steel beams; erect roof formwork support frames and diagonal bracing formwork support frames; after completing the binding of column and beam reinforcement, pour roof and diagonal bracing concrete to complete the construction of the lower and upper roof layers.

[0016] As a preferred option, step S8 is refined as follows: S8.1 Formwork support frame removal After the roof concrete pouring is completed, the formwork and support frame below the suspended layer and the lower step layer are removed, while the temporary columns and elevation adjusters are left in place; then the upper step layer is removed in sequence. After the roof concrete structure reaches the required strength, the roof formwork and support frame are removed; the external cantilever scaffolding is retained for decoration and finishing construction. S8.2 Temporary column removal After the concrete structure reaches its strength, the steel platform is unloaded using an elevation adjuster. During the unloading process, the platform is lowered by 2-4mm each time, and this is done in multiple stages until the temporary column is completely separated from the superstructure, thus completing the unloading. Finally, the temporary column, upper tie rod, and second temporary support are removed. S8.3 steel platform dismantling A bottom decoration construction operation platform was erected on the steel platform. After the cantilevered facade construction of the auditorium was completed, the cantilevered frame was dismantled. After the bottom decoration construction of the auditorium was completed, the operation frame was dismantled. Then the platform distribution beam and the first temporary support were dismantled. Finally, the lower support and the main beam of the platform were dismantled as a whole on the external scaffolding of the lower structure.

[0017] Preferably, a stress sensor is installed on the temporary column, and the stress sensor is communicatively connected to an external monitoring device to monitor the axial load borne by the temporary column in real time.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) Phased load-bearing system with progressively increasing load-bearing capacity: This invention uses a first-stage temporary truss (first temporary diagonal bracing, platform main beam, and lower support) to bear the construction load of the suspended floor. After the suspended floor concrete reaches its strength, a second temporary diagonal bracing and upper tie rod are added to the already constructed suspended floor concrete structure to form the second-stage reinforcing component. This phased load-bearing system allows the load-bearing capacity of the temporary support structure to be progressively increased, precisely matching the construction load requirements, providing high safety redundancy, and meeting the requirements for simultaneous construction of multiple floors.

[0019] (2) Precise and Controllable Elevation and Unloading: This invention features an elevation adjuster at the top of the temporary column. This adjuster consists of two right-angled triangular blocks with opposing inclined surfaces and a through-bolt running through the middle. It has a dual function: first, before the cantilever layer construction, the elevation of the top of the temporary column is precisely adjusted by rotating the through-bolt, ensuring the accuracy of the construction elevation; second, after the entire auditorium construction is completed, the elevation is gradually lowered by slowly rotating the through-bolt (2-4mm each time, completed in multiple stages), achieving a smooth unloading of structural stress and avoiding safety hazards caused by sudden stress changes. This structure is simple, low-cost, and not easily damaged, overcoming the shortcomings of existing technologies such as high-cost, easily damaged, and difficult-to-replace jacks, and the inconvenience of adjusting the sandbox elevation.

[0020] (3) Overall hoisting improves construction efficiency and precision: This invention fixes the lower support to the bottom of the platform's main beam and connects them into an overall hoisting unit before hoisting it into place. This overall hoisting method reduces the amount of on-site high-altitude welding or bolting work, improves installation precision and construction efficiency, and ensures the overall structural performance.

[0021] (4) Highly integrated functions, combining construction and decoration operations: This invention installs cantilevered scaffolding I-beams at the ends and sides of the platform's main beam, upon which cantilevered scaffolding is erected. This cantilevered scaffolding serves as edge safety protection during the construction of the auditorium's upper structure and can be directly used as the external scaffolding for facade decoration in the subsequent decoration phase, eliminating the need for a separate high-altitude work platform and effectively solving the construction problem of no working surface on the exterior of a large cantilever structure. Simultaneously, the spacing of the platform's distribution beams matches the spacing of the formwork support frame uprights, ensuring uniform load distribution.

[0022] (5) Clear load transfer path and information-based monitoring: This invention places temporary columns near the connection point between the platform's main beam and the lower support, with their planar position corresponding to the upper hanging columns. This ensures that the construction loads from each floor are precisely transferred to the temporary columns via the hanging columns, and then to the steel platform, resulting in the shortest and clearest force transfer path. Simultaneously, stress sensors connected to external monitoring equipment are installed on the temporary columns to monitor the axial loads borne by the columns in real time. This allows construction personnel to monitor load transfer at any time, enabling proactive information-based safety control and ensuring the safety of complex structure construction.

[0023] (6) The connection node design is reasonable, easy to install and dismantle, and reliable in terms of force: The lower ends of the first and second temporary diagonal braces of this invention are fixed by through-wall embedded bolt assemblies. The assembly includes a steel sleeve embedded in the concrete column, a steel back plate attached to both sides of the concrete column and a component end plate, as well as anchor bolts and steel pads. During installation, the anchor bolts are inserted into the diagonal braces through the embedded steel sleeves, which facilitates installation and dismantling; the steel back plate and steel pad effectively enhance the load-bearing capacity of the node and prevent local pressure failure.

[0024] (7) Modular reinforcement design to adapt to different span requirements: This invention also provides a variety of reinforcement structures to adapt to different working conditions: When the cantilever span increases or the construction load increases, several small supports can be set between the lower support and the main beam of the platform to form a small truss structure, and small supports can be added between adjacent lower supports and between adjacent main beams of the platform to connect the steel platform laterally into an integral spatial truss system. The above design can be flexibly selected according to the actual project, and has strong applicability. Attached Figure Description

[0025] Figure 1 This is a construction flowchart of the large cantilevered hollow truss auditorium structure of the present invention; Figure 2 This is a schematic diagram of the temporary lower support installation in the first stage of the present invention; Figure 3 This is a schematic diagram illustrating the state of the cantilever scaffolding and formwork support frame erection and the construction of the suspended layer according to the present invention; Figure 4 This is a schematic diagram of the second stage of support installation and upper stepped layer construction of the present invention; Figure 5 This is a schematic diagram showing the state of the steel structure installation completed according to the present invention; Figure 6 This is a schematic diagram showing the state of the structure after construction of the present invention; Figure 7 This is a schematic diagram of the unloading and dismantling process of the present invention. Figure 1 ; Figure 8 This is a schematic diagram of the unloading and dismantling process of the present invention. Figure 2 ; Figure 9 This is a schematic diagram of the unloading and dismantling process of the present invention. Figure 3 ; Figure 10 yes Figure 2 Enlarged view of a portion of point A in the middle; Figure 11 This is a structural schematic diagram of the through-wall pre-embedded bolt assembly of the present invention.

[0026] Explanation of key component symbols: 101. First temporary diagonal brace; 102. Platform main beam; 103. Lower support; 104. Platform distribution beam; 105. Formwork support frame; 106. Cantilevered scaffolding I-beam; 107. Transverse I-beam distribution beam; 108. Cantilevered scaffold; 109. Temporary column; 110. Elevation adjuster; 110a. Right-angled triangular block; 110b. Through bolt; 111. Second temporary diagonal brace; 112. Upper tie rod; 113. Hanging column; 113a. Lower steel column of hanging column; 113b. Upper steel column of hanging column; 114. Embedded bolt assembly; 114a. Steel sleeve; 114b. Steel back plate; 114c. Component end plate; 114d. Anchor bolt; 114e. Nut; 114f. Steel pad; 115. Concrete column; 116. Substructure 117. Tie column; 117a. Tie column steel column; 118. Support column; 118a. Support column lower steel column; 118b. Support column upper steel column; 119. Lower main beam of the staircase; 120. Lower suspension beam; 121. Staircase; 122. Roof steel beam; 123. Upper suspension beam; 123a. Upper suspension beam steel beam; 124. Diagonal brace; 125. Bottom main beam of the staircase; 126. Suspension beam; 126a. Suspended steel beam; 127. Stage frame column; 128. Stage main beam; 129. Stage secondary beam; 130. Side frame column; 131. Middle side beam; 132. Upper main beam of the staircase; 133. Frame column; 134. Upper side beam; 135. Roof main beam; 136. Roof secondary beam; 137. Roof folded beam; 138. Middle main beam of the staircase; 139. Sloping beam of the staircase; ①-Lower structural layer; ②-Suspended layer; ③-Lower stepped layer; ④-Upper stepped layer; ⑤-Lower roof layer; ⑥-Upper roof layer. Detailed Implementation

[0027] The present invention will now be described in further detail with reference to the accompanying drawings: Lecture halls in modern public buildings typically employ a column-free, large-space structure to ensure unobstructed views. To achieve a light, suspended visual effect, the engineers used large cantilevered, open-web trusses as the main structure of the lecture hall. For example... Figure 1As shown, the auditorium's structural floors from bottom to top are: lower structural floor ①, suspended floor ②, lower staircase floor ③, upper staircase floor ④, lower roof floor ⑤, and upper roof floor ⑥; lower staircase floor ③ and upper staircase floor ④ are connected, lower roof floor ⑤ and upper roof floor ⑥ are connected, and the lower staircase floor ③ and suspended floor ② are at the same elevation.

[0028] Please see Figure 1 As shown, the present invention provides a construction method for a large cantilevered open truss auditorium structure, comprising the following construction steps: S1: Detailed Design Determine the construction sequence based on the site structure, and conduct detailed design of the lower support and segmented design of the steel in the steel-concrete composite column.

[0029] S2: Pre-reserved and embedded parts in the substructure Connection points for the first temporary diagonal brace 101, the platform main beam 102, and the lower support 103 are pre-embedded in the substructure 116. Specifically, connection points for the first temporary diagonal brace 101, the platform main beam 102, and the lower support 103 are pre-embedded in the concrete beams and columns of the substructure 116 according to the detailed design requirements. Among them, the first temporary diagonal brace 101 and the platform main beam 102 are tension members, and their connection points use pre-embedded bolts; the lower support 103 is a compression member, and its connection points use pre-embedded steel plates with perforated plug welded anchor bars.

[0030] S3: Install the first phase of temporary lower support A first temporary diagonal brace 101, a platform main beam 102, and a lower support 103 are installed at the corresponding connection point of the lower structure 116. A steel platform is set on the platform main beam 102, and a temporary column 109 is installed near the connection point of the platform main beam 102 and the lower support 103.

[0031] Please see Figure 2 As shown, after the concrete pouring of the substructure 116 is completed, the specific steps for the installation of the temporary substructure support in the first stage are as follows: S3.1 Install the first temporary diagonal brace: Install the first temporary diagonal brace 101 at the corresponding connection point, connecting both ends of it to the concrete beam-column joint of the lower structure 116. The upper end of the first temporary diagonal brace 101 is fixedly connected to the concrete structure using pre-embedded bolts, and its lower end is fixed using through-wall pre-embedded bolt assembly 114; as shown... Figure 11As shown, the through-wall embedded bolt assembly 114 includes a steel sleeve 114a embedded in the concrete column 115, a steel back plate 114b attached to both sides of the concrete column 115, a component end plate 114c, and an anchor bolt 114d. The component end plate 114c is fixed to the bottom of the first temporary diagonal brace 101. The anchor bolt 114d passes through the steel back plate 114b, the steel sleeve 114a, and the component end plate 114c in sequence and is locked by a nut 114e. Steel pads 114f are provided between the head of the anchor bolt 114d and the steel back plate 114b, and between the nut 114e and the component end plate 114c, to enhance the bearing capacity of the joint and prevent local pressure failure.

[0032] S3.2 Install the main beam and lower support of the platform: Fix the lower support 103 to the bottom of the main beam 102 of the platform and weld them together to form an integral hoisting unit. Use a crane to hoist the entire unit into place, so that the main beam 102 of the platform cantilevered outside the lower structure 116, and the lower support 103 connects the bottom of the main beam 102 of the platform to the lower structure 116. The main beam 102 of the platform is fixedly connected to the concrete structure by pre-embedded bolts; the lower support 103 is fixedly connected to the concrete structure by steel plate pre-embedded parts for anchoring reinforcing bars through perforated plug welding.

[0033] At this time, the first temporary diagonal brace 101, the platform main beam 102, the lower support 103, and the structural beams and slabs work together to form a stable temporary truss structure to support the construction of the upper large cantilevered open truss auditorium.

[0034] It is worth noting that when the cantilever span increases or the construction load increases, several small supports (such as diagonal braces) are added between the lower support 103 and the platform main beam 102 to form a small truss structure, which is used to increase the cantilever span and increase the load-bearing capacity. At the same time, small supports are cross-connected between adjacent lower supports 103 and adjacent platform main beams 102 to connect the steel platform laterally into an overall spatial truss system, which significantly enhances the lateral stability and integrity of the steel platform.

[0035] S3.3 Laying Platform Distribution Beams: Platform distribution beams 104 are laid on the main beam 102 of the platform and connected by welding to form a steel platform.

[0036] S3.4 Install temporary columns: Install temporary columns 109 near the connection point between the platform main beam 102 and the lower support 103. The planar position of the temporary columns 109 corresponds to the position of the upper hanging column 113. The function of the temporary columns 109 is to directly transfer the construction load from the upper hanging column 113 to the steel platform below.

[0037] S4: Erect formwork support frames and cantilevered scaffolding A formwork support frame 105 is erected on the steel platform, and a cantilevered scaffolding 108 is erected on its outer side. The specific construction details are as follows: Please see Figure 3 As shown, a formwork support frame 105 is erected on the steel platform formed by the platform distribution beam 104 to support the beam and slab formwork of the cantilever layer ②. The spacing of the uprights of the formwork support frame 105 is consistent with the arrangement spacing of the platform distribution beam 104, so that the load of the uprights of the formwork support frame 105 is evenly transferred to the platform main beam 102 through the platform distribution beam 104.

[0038] Please see Figure 3 As shown, cantilevered scaffolding I-beams 106 are installed at the ends and sides of the platform main beam 102. The cross-section of the cantilevered scaffolding I-beams 106 is smaller than that of the platform main beam 102. Transverse I-beam distribution beams 107 are installed on the cantilevered scaffolding I-beams 106, and cantilevered scaffolding 108 is erected on the transverse I-beam distribution beams 107, and the cantilevered scaffolding 108 is connected and fixed to the platform distribution beams 104 and the platform main beam 102. The cantilevered scaffolding 108 serves as edge safety protection during construction and as an operating platform in the subsequent decoration stage.

[0039] S5: Construction of the lower stepped floor and suspended floor Install an elevation adjuster 110 on the top of the temporary column 109, adjust it to the required height for support, set up the formwork, and pour the floor concrete.

[0040] Please see Figure 3 As shown, the specific construction steps for the lower stepped layer ③ and the suspended layer ② are as follows: S5.1 Install the supporting steel columns: Install supporting steel columns 118a on both sides of the horizontal axis of the auditorium. The connection nodes of the supporting steel columns are set 0.5-1m above the steps to facilitate subsequent connections.

[0041] S5.2 Structural column construction: Construction of the structural columns under the lower stepped layer ③ and suspended layer ②, including tie columns 117, support columns 118, stage frame columns 127, and side frame columns 130, and simultaneous erection of formwork support frames (temporary scaffolding).

[0042] S5.3 Install the elevation adjuster: Install the elevation adjuster 110 on the top of the temporary column 109. (Example) Figure 10 As shown, the elevation adjuster 110 includes two right-angled triangular blocks 110a with their inclined surfaces facing each other, and a through screw 110b passing through the middle of the two right-angled triangular blocks 110a. The relative position of the two triangular blocks is adjusted by rotating the through screw 110b to change the elevation. After adjusting to the required height for erection, the template is erected.

[0043] S5.4 Installation of Suspended Columns and Suspension Beams: Multiple suspended column steel columns 113a are installed at intervals along the transverse direction of the auditorium. The positions of the suspended column steel columns 113a correspond to the planar positions of the temporary columns 109, and the suspended column steel columns 113a are connected to the suspension beams 126a. To ensure safety during installation, the height of the suspended column steel columns 113a is only 0.5-1m above the suspension layer to prevent tipping. The suspended column steel columns 113a directly transfer the construction load from the upper part to the temporary columns 109 below.

[0044] S5.5 Setting up connection points for tie columns: Install anchor bolts for tie columns 117a on the upper surface of both ends of the main beam 119 under the steps, reserving connection points for subsequent installation of tie columns 117.

[0045] S5.6 Setting up diagonal brace connection points: Reserve steel bar joints for the second temporary diagonal brace 111 on both sides of the horizontal axis of the auditorium.

[0046] S5.7 Pouring floor concrete: After completing the reinforcement binding of beams and slabs such as the bottom main beam 125 of the staircase, the lower main beam 119 of the staircase, the stage main beam 128, the stage secondary beam 129, and the suspended beam 126, pour the floor concrete to complete the construction of the lower staircase layer ③ and the suspended layer ②.

[0047] It is worth noting that stress sensors (not shown in the figure) can be installed on temporary columns 109 before concrete pouring. These sensors can communicate with external monitoring equipment (such as computers and data acquisition devices). The stress sensors monitor the axial load of the temporary columns 109 in real time and transmit the monitoring data to the external monitoring equipment. Construction personnel can monitor the stress status of each temporary column at any time, and construction can be immediately suspended and reinforcement measures can be taken if abnormal loads are detected. This information-based monitoring method ensures the safety of complex structure construction.

[0048] S6: Second-stage support installation Please see Figure 4 As shown, after the concrete of the lower stepped layer ③ and the suspended layer ② reaches the design strength and the formwork is removed, the second temporary diagonal brace 111 and the upper tie rod 112 are installed. The lower end of the second temporary diagonal brace 111 is also fixed by the through-wall pre-embedded bolt assembly 114; specifically, the bottom of the second temporary diagonal brace 111 is fixed to the end plate 114c of the component, a steel sleeve 114a is embedded in the concrete column, and steel back plates 114b and end plates 114c of the component are attached to both sides of the concrete column. The anchor bolt 114d passes through the steel back plate 114b, the steel sleeve 114a and the end plate 114c of the component in sequence and is locked by the nut 114e. Steel pads 114f are set between the head of the anchor bolt 114d and the steel back plate 114b, and between the nut 114e and the end plate 114c of the component, in order to enhance the joint bearing capacity and prevent local pressure failure.

[0049] Second temporary diagonal braces 111 and upper tie rods 112 are installed on both sides and in the middle area of ​​the lecture hall. The specific installation method is as follows: For the two sides of the auditorium: the lower end of the second temporary diagonal brace 111 is connected to the tie column 117, and the upper end is connected to the support column 118; the upper end of the upper tie rod 112 is connected to the support column 118, and the lower end is connected to the platform main beam 102.

[0050] For the central area of ​​the auditorium: the two ends of the second temporary diagonal brace 111 are connected to the adjacent lower columns respectively; the upper end of the upper tie rod 112 is connected to the lower column, and the lower end is connected to the platform main beam 102.

[0051] The second temporary diagonal brace 111 and the upper tie rod 112 constitute a "tie-brace" system, which transforms the already constructed suspended concrete structure into part of the entire support system, increasing the overall load-bearing capacity of the cantilever truss.

[0052] S7: Layered construction steps, upper step layer and roof layer.

[0053] Please see Figure 5 , Figure 6 As shown, the specific construction steps for the steps, the upper step layer, and the roof layer are as follows: S7.1 Construction of the staircase and upper staircase: Erect cantilever scaffolding 108 and tie it to the lower suspended beam 120 structure; after the suspended layer concrete reaches its strength, install the upper steel column 113b to the roof; erect the formwork support frame 105 on the suspended layer ② and carry out the structural construction of the staircase 121 and upper staircase ④; after completing the reinforcement binding of the main beam 138, upper main beam 132, middle side beam 131, inclined beam 139, and staircase 121, pour concrete to complete the structural construction of the staircase 121 and upper staircase ④.

[0054] S7.2 Roofing Construction: Install steel columns 118b on the support columns, complete the installation and alignment of the roof steel beam 122 between the support columns 118 and the hanging columns 113, and simultaneously complete the installation and alignment of the upper hanging beam steel beam 123a; install tie columns 117 on both sides of the lower step layer ③ to the roof, and complete the installation and alignment of the roof steel beam 122; erect the roof formwork support frame and the formwork support frame for the diagonal braces 124, and complete the reinforcement binding of columns such as hanging columns 113, tie columns 117, support columns 118, stage frame columns 127, frame columns 133, as well as beams and slabs such as upper hanging beam 123, upper side beam 134, roof main beam 135, roof secondary beam 136, and roof folded beam 137, and then pour the roof and diagonal brace concrete to complete the construction of the lower roof layer ⑤ and the upper roof layer ⑥.

[0055] S8 Unloading and Removal Please see Figures 7 to 9 As shown, the specific steps include: S8.1 Formwork Support Removal: After the roof concrete pouring is completed, remove the formwork and support frame below the suspended layer ② and the lower step layer ③, leaving the temporary column 109 and the elevation adjuster 110 in place; then remove the upper step layer ④, the lower roof layer ⑤ and the upper roof layer ⑥ in sequence. After the concrete structure strength reaches 100%, remove the roof layer formwork and formwork support frame; the external cantilever scaffolding 108 is retained for decoration and finishing construction.

[0056] S8.2 Temporary Column Removal: After the concrete structure reaches 100% strength, the steel platform is unloaded using the elevation adjuster 110. During unloading, the through bolts 110b of the elevation adjuster 110 are slowly adjusted to gradually lower the elevation of the adjuster until the temporary column 109 is completely detached from the superstructure, completing the unloading. Finally, the temporary column 109, the upper tie rod 112, and the second temporary diagonal brace 111 are removed.

[0057] Specifically, during the unloading process, the structure is lowered by 2-4 mm each time by using the through bolt 110b, with a 10-15 minute interval between each unloading operation to fully release structural stress. The entire unloading process is completed in 5-10 stages. For ultra-large span structures, the number of unloading operations can be increased to 15, with each stage lowering the structure by 1-2 mm. This parameter optimization further ensures the smoothness and safety of the unloading process.

[0058] S8.3 Steel Platform Dismantling: Erect a bottom decoration construction operation platform on the steel platform. After completing the cantilevered facade construction of the auditorium, dismantle the cantilevered scaffolding. After completing the exterior decoration construction of the bottom of the auditorium, dismantle the operation frame. Then dismantle the platform distribution beam 104 and the first temporary diagonal brace 101. Finally, dismantle the combined components of the lower support 103 and the platform main beam 102 as a whole.

[0059] The construction method of the large cantilevered hollow truss auditorium structure of the present invention is reasonable, easy to operate, and safe and reliable.

[0060] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be covered by the claims of the present invention.

Claims

1. A construction method of a large cantilevered open-web truss auditorium structure, characterized by, The construction steps include the following: S1: Detailed Design Determine the construction sequence based on the site structure, and conduct detailed design of the lower support and segmented design of the steel in the steel-concrete composite column. S2: Pre-reserved and embedded parts in the substructure The connection points of the first temporary diagonal brace, the platform main beam, and the lower support are pre-embedded in the substructure; S3: Install the first phase of temporary lower support The first temporary diagonal brace, the platform main beam, and the lower support are installed at the corresponding connection point of the lower structure. A steel platform is set on the platform main beam, and temporary columns are installed near the connection point of the platform main beam and the lower support. S4: Erect formwork support frames and cantilevered scaffolding A formwork support frame is erected on the steel platform, and a cantilevered scaffold is erected on its outer side; S5: Construction of the lower stepped floor and suspended floor Install an elevation adjuster on the top of the temporary column, adjust it to the required height for support, erect the formwork, and pour the floor concrete. S6: Second-stage support installation After the concrete of the lower stepped layer and the suspended layer reaches the required strength and the formwork is removed, the second temporary diagonal brace and the upper tie rod are installed on the concrete structure. S7: Construction steps, upper step layer and roof layer; S8: Unloading and removal; After the roof concrete pouring is completed, the formwork and formwork support frame are removed from bottom to top; after removal, the formwork is unloaded using the elevation adjuster; after unloading, the temporary columns, upper tie rods, second temporary supports, cantilever scaffolding, platform distribution beams, first temporary supports, lower supports, and platform main beams are removed in sequence.

2. The construction method of a large cantilevered hollow truss auditorium structure according to claim 1, characterized by, Step S3 is further refined as follows: S3.1 Install the first temporary diagonal brace: After the concrete of the lower structure is poured, the first temporary diagonal brace is installed at the corresponding connection point. The pre-embedded first temporary diagonal brace is used as a tension member and is fixedly connected to the concrete structure by pre-embedded bolts. The lower end of the first temporary diagonal brace is fixed by a through-wall pre-embedded bolt assembly. S3.2 Install the main beam and lower support of the platform: Fix the lower support to the bottom of the main beam of the platform and connect them into an integral hoisting unit, and then hoist the whole unit into place; The main beam of the platform, as a tension member, is fixedly connected to the concrete structure with pre-embedded bolts; The lower support, as a compression member, is fixedly connected to the concrete structure with steel plate pre-embedded parts for anchoring steel bars by perforation and plug welding. S3.3 Laying Platform Distribution Beams: Platform distribution beams are laid on the main beam of the platform to form the steel platform. The spacing of the platform distribution beams is consistent with the spacing of the uprights of the formwork support frame. S3.4 Install temporary columns: Install temporary columns near the intersection of the platform main beam and the lower support.

3. The construction method of a large cantilevered hollow truss auditorium structure according to claim 2, characterized by, When the cantilever span increases or the construction load increases, several small supports are added between the lower support and the main beam of the platform to form a small truss structure, and small supports are added between adjacent lower supports and between adjacent main beams of the platform to connect the steel platform laterally into a whole.

4. The construction method of a large cantilevered hollow truss auditorium structure according to claim 2, characterized by, The through-wall embedded bolt assembly includes: a steel sleeve embedded in the concrete column, a steel back plate and a component end plate attached to both sides of the concrete column, and an anchor bolt; the component end plate is fixed to the bottom of the first temporary diagonal brace, and the anchor bolt passes through the steel back plate, the steel sleeve and the component end plate in sequence and is locked by a nut, and a steel washer is provided between the head of the anchor bolt and the steel back plate, and between the nut and the component end plate.

5. The construction method of a large cantilevered hollow truss auditorium structure according to claim 2, characterized by, In step S4, cantilevered scaffolding I-beams are installed at the ends and sides of the main beam of the platform. The cross-section of the cantilevered scaffolding I-beams is smaller than that of the main beam of the platform. Transverse I-beam distribution beams are installed on the cantilevered scaffolding I-beams. The cantilevered scaffolding is then erected on the transverse I-beam distribution beams. The cantilevered scaffolding is connected to the platform distribution beams and the main beam of the platform.

6. The construction method for the large cantilevered open-web truss auditorium structure according to claim 5, characterized in that, Step S5 is further refined as follows: S5.1 Install supporting steel columns: Install supporting steel columns on both sides of the auditorium, with the connection nodes of the supporting steel columns being 0.5-1m higher than the upper surface of the steps; S5.2 Structural column construction: Construct the structural columns under the lower stepped floor and suspended floor, and erect formwork support frames simultaneously; S5.3 Install elevation adjuster: Install elevation adjuster on top of the temporary column. The elevation adjuster includes two right-angled triangular blocks with their inclined surfaces touching each other, and a through screw rod passing through the middle of the two right-angled triangular blocks. The relative position of the two triangular blocks is adjusted by rotating the through screw rod to change the elevation. Adjust it to the height required for support and support the template. S5.4 Install the steel columns under the suspended columns and the steel beams of the suspension beams: Install multiple steel columns under the suspended columns at intervals along the transverse direction of the auditorium. The position of the steel columns under the suspended columns corresponds to the plane position of the temporary columns. The top of the steel columns under the suspended columns after installation is 0.5-1m higher than the upper surface of the suspension layer. S5.5 Setting tie column steel column connection points: Install anchor bolts for tie column steel columns on the upper surface of both ends of the main beam under the steps; S5.6 Setting diagonal brace connection points: Reserve steel bar joints for diagonal braces on both sides of the horizontal axis of the auditorium; S5.7 Pouring floor concrete: After completing the binding of beam and slab reinforcement, pour floor concrete to complete the construction of the lower stepped floor and suspended floor.

7. The construction method of a large cantilevered hollow truss auditorium structure according to claim 6, characterized by, In step S6, second temporary diagonal braces and upper tie rods are installed on both sides and in the middle area of ​​the auditorium. The lower end of the second temporary diagonal brace is fixed with a through-wall pre-embedded bolt assembly. The installation method of the second temporary diagonal brace and the upper tie rod is as follows: For the two sides of the auditorium, the lower end of the second temporary diagonal brace is connected to the tie column and the upper end is connected to the support column, and the upper end of the upper tie rod is connected to the support column and the lower end is connected to the platform main beam; For the middle area of ​​the auditorium, the two ends of the second temporary diagonal brace are connected to the adjacent lower column respectively, and the upper end of the upper tie rod is connected to the lower column and the lower end is connected to the platform main beam.

8. The construction method of a large cantilevered hollow truss auditorium structure according to claim 7, characterized by, Step S7 is further refined as follows: S7.1 Construction of the steps and upper steps: Erect cantilever scaffolding and tie it to the lower suspended beam structure; after the concrete of the suspended layer reaches the strength, install the steel columns on the suspended columns to the roof; erect the formwork support frame on the suspended layer, tie the beam and slab reinforcement of the steps and upper steps, and pour concrete to complete the structural construction of the steps and upper steps. S7.2 Roofing construction: Install steel columns on the support columns, complete the installation and alignment of the roof steel beams between the support columns and the hanging columns, and simultaneously complete the installation and alignment of the upper hanging beam steel beams; install tie columns on both sides of the lower step to the roof, and complete the installation and alignment of the roof steel beams; erect roof formwork support frames and diagonal bracing formwork support frames; after completing the binding of column and beam reinforcement, pour roof and diagonal bracing concrete to complete the construction of the lower and upper roof layers.

9. The construction method of a large cantilevered hollow truss auditorium structure according to claim 8, characterized by, Step S8 is further refined as follows: S8.1 Formwork support frame removal After the roof concrete pouring is completed, the formwork and support frame below the suspended layer and the lower step layer are removed, while the temporary columns and elevation adjusters are left in place; then the upper step layer is removed in sequence. After the roof concrete structure reaches the required strength, the roof formwork and support frame are removed; the external cantilever scaffolding is retained for decoration and finishing construction. S8.2 Temporary column removal After the concrete structure reaches its strength, the steel platform is unloaded using an elevation adjuster. During the unloading process, the platform is lowered by 2-4mm each time, and this is done in multiple stages until the temporary column is completely separated from the superstructure, thus completing the unloading. Finally, the temporary column, upper tie rod, and second temporary support are removed. S8.3 steel platform dismantling A bottom decoration construction operation platform was erected on the steel platform. After the cantilevered facade construction of the auditorium was completed, the cantilevered frame was dismantled. After the bottom decoration construction of the auditorium was completed, the operation frame was dismantled. Then the platform distribution beam and the first temporary support were dismantled. Finally, the lower support and the main beam of the platform were dismantled as a whole on the external scaffolding of the lower structure.

10. The construction method of a large cantilevered hollow truss auditorium structure according to claim 1, characterized in that, A stress sensor is installed on the temporary column, and the stress sensor is connected to an external monitoring device to monitor the axial load borne by the temporary column in real time.

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