Composite wood-concrete column with fire resistance capability

Abstract

The current invention deals with a hybrid wood-concrete column, tackling the critical challenges of fire resistance, structural integrity, and environmental sustainability in today's construction. The column comprises three main parts including a wooden central core covered with the intumescent fire-retardant coating, an outer concrete jacket with additives like micro-silica and polypropylene fibers to boost both its thermal resistance and compressive strength, and a layer of insulation to greatly reduce heat transfers between the core and jacket. The hybrid design synergistically distributes tensile and compressive forces, enabling a high load-bearing capacity of at least 1.3 MN while maintaining lightweight properties for dynamic stability in seismic zones. This composite column shows a 63% reduction in heat transfer compared to conventional systems, ensuring prolonged fire resistance. It is ideal for tall buildings, infrastructure that can withstand disasters, modular construction, and projects that need updating, providing a strong, affordable, and eco-friendly answer to modern engineering issues.

Description

[0001]Description Title of Invention: Composite Wood-Concrete Column with Fire Resistance Capability] Technical Field: [ Civil engineering, Architecture] Background Lately, wood as a main construction material has received a lot of favorable reception from people, civil engineers, and contractors because it is environmentally friendly, lightweight, and affordable. However, one of the main challenges regarding the utilization of wooden material in framed buildings is the aspect of fire resistance or inflammability. Indeed, wood is a flammable material that has huge potential to cause large-scale floorage of buildings in residential, commercial, and industrial areas in the event of fire disasters. Still, concrete enjoys vast popularity with fire resistance as well as the load-bearing capacity at elevated temperatures. It is non-combustible and does well in safeguarding structural members in case of fire-related accidents. However, working in concrete is costly because concrete is heavy, not friendly to the environment, and cannot be shaped like wood. Introducing composite wood-concrete columns is a solution to these challenges because it is based on the best characteristics of both materials. Wood allows the manufacturing of light, sustainable, and versatile structures, and the concrete shell moderates the fire risk on the wooden veneer for better security and sturdiness. Prior studies on the construction of composite wood-concrete systems have considered general loading conditions but did not consider fire sensitivity. These solutions are generally characterized by the absence of efficient insulation between the wood and the concrete: heat exchange that distorts the wood core when exposed to high temperatures for an extended period. They also do not utilize higher performing materials and chemicals, for example, fire resistance coatings and heat-bearing fibers that can greatly improve fire performance. These limitations are overcome in this invention by incorporating new fire-resistant material and methods to fabricate a wood-concrete composite column exclusively suitable for fire conditions and which will not impair the structural strength. This progression harmonizes fire safety with sustainable construction so that it forms an even better fit for contemporary architectural and engineering pursuits. Summary of Invention The invention pertains to a composite wood-concrete column which is intended to fulfill the requirements of the contemporary construction regarding not only the strength and stiffness of the specialized structures but also their fire endurance capacity. The column also includes a wooden structure laminated with concrete jackets using a concrete mix incorporating heat- resistant materials. The composite material integrates the lightness and renewability of timber accompanied by the heat resistance and strength of concrete, making the hybrid the universal construction material for domestic, office, and industrial uses. Key features of the invention include: 1. Fire Resistance: The concrete jacket is enhanced with fire-resistant additives, such as micro-silica and polypropylene fibers, to prevent heat transfer and protect the wooden core during prolonged exposure to high temperatures. 2. Thermal Insulation Layer: A layer of thermal insulating material, such as silicate boards or geopolymer-based coatings, is incorporated between the wood and concrete to further minimize heat transfer and enhance fire performance. 3. Mechanical Strength: The composite structure effectively distributes loads between the wood core and concrete jacket, providing high compressive and flexural strength. 4. Sustainability: The use of renewable wood materials and optimized concrete formulations reduces the environmental impact of construction while maintaining high performance. 5. Lightweight Design: Compared to fully concrete columns, the composite column is significantly lighter, enabling easier transportation, handling, and installation. The following are the inventive features in this case: Fire Resistance: Micro-silica and polypropylene fibers are added to the concrete jacket to further restrict any transfer of heat to the wooden core and protect it in case of prolonged exposure to heat. Thermal Insulation Layer: To curb the transfer of heat to the maximum, a layer of silicate boards or geopolymeric coating is placed between the wood and concrete to improve performance in terms of fire. Mechanical Strength: The composite structure efficiently bears the loads as these are distributed between the wooden core and concrete jacket thus bestowing the structure with high levels of compressive and flexural strength. Sustainability: The formulation of concrete coupled with the use of wooden materials that can be replenished negates environmental challenges that may emanate from construction but yield high performance. Lightweight Structure: The composite column is lighter than the fully concrete column and therefore is easier to transport, handle, and fix. The construction method begins with the manufacture of a wooden core coated with fire- resistant materials, which is followed by the casting of a concrete exterior layer over the core using custom molds. To enhance its mechanical and thermal properties, the concrete is cured in controlled conditions. The design developed in the current patent is particularly applicable for buildings in fire-prone areas, as it offers greater safety, structural strength, and environmental benefits. It is an effective way to overcome major flaws inherent in traditional construction methods by combining fire resistance and sustainability in an integrated and efficient design. Technical Challenge The following patent tackles several major technical problems in using wood with concrete in construction, including fire resistance, structural integrity, and sustainability. It solves the following main technical challenges: 1. The combustibility of wood. • Fire risk: As a combustible material, wood can undergo rapid structural failure in the case of fire, restricting its application in construction, especially for buildings with high fire risk. • Solution: The concrete encasement of the composite column acts as a fire shield, protecting the wooden core from direct exposure to flames. The inclusion of fire-resistant additives in the concrete mix, coupled with an added layer of thermal insulation, significantly hinders the transmission of heat, preserving the structural integrity of the wooden core even under high-temperature conditions. eat Transfer Between Concrete and Wood • Problem: In conventional composite designs, heat transfer from the concrete jacket to the wooden core during a fire compromises the wood’s structural properties, leading to early failure. • Solution: The invention incorporates a thermal insulation layer, such as silicate boards or geopolymeric coatings, between the wood and concrete. This layer reduces the rate of heat conduction, ensuring the core remains structurally stable for a longer duration. Not Appropriate Fire Resistant Concrete Mix • Problem: Conventional forms of concrete are incombustible, however when exposed to high temperatures they may crack or lose their structural integrity as a result of thermal stress. • Solution: The package solutions include the concrete jacket improved with micro-silica and polypropylene fibers making it more thermal resistant and less likely to crack when exposed to fire. Altogether these additives enhance the overall durability and load carrying capacity in the design of the column. 4. Environmental Sustainability • Problem: Reinforced concrete columns used in the conventional design have high embodied energy, particularly associated with cement, which produces high CO₂ emissions. Also, using only concrete does not meet the current trends of green buildings that look for renewable setting materials. • Solution: In the present work, the invention is made from a renewable wooden core embedded in concrete, this has the effect of minimizing the amount of concrete used in the formation of the column hence leading to a reduced carbon footprint. The benefit of eco- friendly components to the design is achieved while not mislaying functionality. oncrete Structures are heavy • Problem: Fully concrete columns are also cumbersome hence they prove difficult to transport, maneuver, and place especially where prefabricated construction methods are used. • Solution: The use of a wooden core element implies a lower weight of the column’s composite since it is easier for transportation and installation while achieving high mechanical properties. 6. The combined column should have an integrated function against dynamic loads • Problem: Composite columns will in most cases have to deal with compressive, tensile, or flexural force at different times and under different circumstances, for instance, dynamic loads like wind or earthquake forces. • Solution: The innovative structure that marries the tensile characteristics of timber and the compression strengths of concrete is particularly useful. This way the load distribution and the structure's performance in both dynamic and static states are enhanced. 7. Normal Fire-resistant Designs lack attractiveness • challenge: Heat-resistant materials often restrict the architectural beauty and design flexibility of constructed buildings. • Solution: Utilizing a wooden façade along with a concealed concrete jacket enhances the natural appearance of the composite column while providing fire protection. The present patent tackles some of the key challenges witnessed in the modern construction industry and proposes a solution that merges fire safety, structural integrity, and eco-friendly principles. The patent outlines a method for safely integrating wood into structural building systems, particularly in fire-prone areas, while also enhancing the sustainability, efficiency, and environmental impact of buildings. Solution to Problem With the present invention, some challenges about fire resistance, integrity of structures, and environmental sustainability of composite columns made of wood-concrete are overcome through some revolutionary solutions. I discuss the following technical solutions with structured effectiveness analyses: 1. Resistance against fire Textual discussion Problem: Wood is a flammable material and structural failure can occur at high temperatures; concrete is nonflammable but can exfoliate or fracture due to the thermal strains (internal forcing) driven by fire. Solution: • Advanced concrete jacket: The concrete jacket is then manufactured with high-performance additives, micro-silica fibers, and polypropylene, which leads to improved thermal properties by densifying the matrix and, at the same time preventing spallation. A thermal insulation layer such as silicate sheets or geopolymer coatings is placed between the concrete and the wood to significantly reduce heat transfer. • Fireproof coating: The wood core is coated with flame-retardant paint, which expands upon heating and acts as a flame-retardant barrier beneath the surface of the wood. Impact: These innovations cause a delay in the conduction of heat to the wooden core allowing the column to retain its strength during long exposure to the hot environment. Analysis Key Results: Thermal transfer through the column system is 63% less than that of baseline concrete providing excellent fire resistance. 2. Structural Integrity Textual Discussion Problem: Combining materials with vastly different mechanical properties, such as wood and concrete, usually results in poor load distribution, leading to stress concentrations and the possibility of failure due to dynamic loads like wind or earthquakes. Solution: • Synergistic Load Distribution: - Tensile and flexural loads are taken by the wood core, while compressive and shear forces are absorbed by the concrete jacket. • Optimized Bonding: - Mechanical bonding between wood and concrete ensures effective load sharing, thereby minimizing the stress concentrations. • Dynamic Load Optimization: - Due to a reduction in overall weight by use of a wood core, the column would have increased natural frequency which results in resistance to dynamic forces like seismic. Impact: Employing this combined approach can help ensure that the column maintains its structural integrity under both static and dynamic conditions, resulting in an extended lifespan and enhanced safety. Analysis Key Results: • The hybrid column can withstand around 1.3 MN of load while maintaining a stable dynamic response, making it applicable for quake-prone zones and high-stress environments. Conclusion This invention proposes technical solutions that effectively resolve the problems of fire resistance and structural performance: Fire Resistance: Cut heat transfer by 63%, which means it could withstand fire for longer. Structural Integrity: 1.3 MN load capacity achieved through load distribution & load sharing effect and enhanced dynamic stability. The composite wood-concrete column, through these innovations, stands poised as a game- changer for contemporary structures, especially in fire-susceptible and high-demand environments. The two key aspects, fire resistance and structural integrity, are described further along with sample calculations demonstrating the efficacy of this invention. 1. Fire Resistance Thermal Analysis These jackets are reinforced with advanced heat-resistant additives that decrease thermal conductivity and spalling. Its thermal resistance can be computed based on Fourier’s law of heat conduction: Where q is the Heat transfer rate (W), • k denotes the Thermal conductivity of concrete (W / m.K), A represents the Surface area of the concrete jacket (^^2), ∆^^ is the Temperature difference between the exposed surface and core (K) and d represents Thickness of the concrete jacket (m) Improved Concrete Properties: • Baseline Concrete Thermal Conductivity: k = 1.8 W / m\cdotpK • Enhanced Concrete with Additives: k = 1.1 W / m\cdotpK • Jacket Thickness (d): 0.1 m • Surface Area (A): 1.2 m2For a temperature difference of ∆^^ = 800 K: 1.8.1.2.80017,280 ^^ 10,560 ^^Result: The enhanced concrete decreases heat transfer by 39%, protecting the wooden core for a longer time. Thermal Barrier Insulation The addition of a 5 mm silicate board layer with thermal conductivity of k = 0.15 W / m\cdotpK further increases fire resistance. Combined thermal resistance (^^total) for jacket + insulation: ^^total Heat transfer with insulation: ∆^^ 800 ^^insulated= = ^^= 6,452^^total0.124 Result: Adding the thermal barrier decreases the heat transfer by an additional 39%, bringing the total reduction to 63% compared to the baseline. 2. Structural Integrity Load-Bearing Analysis The composite column takes advantage of both the compressive strength of concrete and the tensile strength of wood. Key Properties: • Concrete (Enhanced Mix): • Compressive Strength: ^^^^′= 40 MPa• Cross-sectional Area: ^^^^ = 0.03 ^^2Load Capacity: ^^^^ = ^^^^. ^^^^′^^^^ = 0.03 .40 = 1.2 ^^^^• Wood Core:• Tensile Strength: ^^^^ = 5 ^^^^^^• Cross-sectional Area: ^^^^ = 0.02^^2• Load Capacity: ^^^^ = ^^^^ . ^^^^^^^^ = 0.02 .5 = 0.1^^^^Total Load Capacity: ^^^^^^^^^^^^ = ^^^^ + ^^^^ = 1.2 + 0.1 = 1.3^^^^Dynamic Load Performance For quake or wind-caused dynamic loads, the composite design mitigates stresses via load distribution: Where f is the Natural frequency of the column (Hz), k denotes the Stiffness of the column (N / m), and m is the Mass of the column (kg). A decrease in the overall weight by using the wooden core, mass (m) decreases, increasing the natural frequency, which enhances resistance to dynamic forces. Positive Effects of Invention Several technical and practical advantages are achieved by using the fire-resistant composite wood-concrete column, directly meeting several key challenges posed by present-day construction. The key advantageous effects of this invention are presented below: 1. Better fire resistance The concrete jacket, impregnated with heat-insulating additives, gives excellent protection to the wooden core, greatly retarding the transfer of heat in case of exposure to fire. • The addition of the thermal insulation layer further increases the fire performance of this column, ensuring that even under prolonged high temperatures, the wooden core retains its structural integrity. The technology makes it easy to comply with strict fire safety regulations, making it suitable for high-risk environments. 2. Advanced Structural Integrity The hybrid design takes advantage of the compressive strength inherent in concrete and the tensile strength characteristic of wood, resulting in a column with good performance under both static and dynamic loading conditions. The strong mechanical bond formed between the concrete encasement and the wooden core provides efficient load distribution, which reduces stress concentrations and increases durability. 3. Portable design The use of a wooden core significantly reduces the total weight of the column when compared to all-concrete alternatives. • The light weight of the column makes transportation, handling, and installation easier, especially in prefabricated or modular construction. 4. Ecological Sustainability The use of renewable wood as a structural component reduces the carbon footprint of the column. The concrete mix design combines sustainable approaches: supplementary cementitious materials—such as fly ash or slag—are thereby tremendously added to its environmental sustainability. 5. Economic Efficiency • Reduced maintenance costs with enhanced resistance to fire and structural strength. • Lightweight design reduces transport and installation costs. •Material costs are saved by minimizing concrete application without compromising on performance. 6. Versatility in Applications • Suitable for a wide range of structural applications, including residential, commercial, and industrial buildings. • Suited for high-hazard fire-risk sites, such as warehouses, data centers, and high-rise buildings. 7. Longer Service Lives •The column's durability and resistance to environmental and fire-related stresses significantly extend its lifespan, therefore reducing the need for frequent replacements or repairs. This gives improved protection against thermal degradation and preserves the aesthetic and structural values of the wood. 8. Aesthetic Adaptability The natural aesthetic feature of wood can be retained for visual appeal while the concrete casing can be finished with different architectural finishes to meet various design requirements. This flexibility allows creative architectural applications while maintaining both safety and functionality. The present invention provides a new solution that incorporates fire resistance, structural effectiveness, and sustainability in one design concept. It contains none of the disadvantages traditionally associated with columns but many advantages for modern construction requirements and, therefore, represents a pioneering, functional solution for a host of applications. Brief Description of Drawings [Table 1: Fire Resistance Analysis • A cross-sectional drawing of the composite column shows the following: - Concrete Jacket: It is depicted on the surface as an outer shell, labeled with annotations of augmented fillers (i.e., micro-silica and polypropylene fibers). - Thermal Insulation Layer: Set between the concrete jacket and the wooden core, and visually marked with a different color to indicate its function in limiting heat transfer. - Wooden Core: The central core, labeled with fire-retardant coating properties. •Diagram containing arrows showing heat flow paths, with corresponding numerical annotations for heat resistance and transfer rates. Table 2: Structural Integrity Analysis Brief Description of Drawing: • A load distribution diagram featuring: - Concrete Jacket: Presented by compressive load vectors acting on its outer surface, which can be explained by its ability to support compressive and shear forces. - Wood Core: implicated in the core with tensile load arrows showing its capacity to resist flexural and tensile loads. - Combined Load Interaction: The diagram illustrates the mechanics of load sharing between the materials using arrows and the dynamic aspects are considered for seismic performance. Table 3: Heat Transfer Calculations Brief Description of Drawing: • A thermal gradient schematic illustrating: o The outer concrete surface, identified as the highest temperature zone exposed to fire. o Heat flow paths, passing through the concrete jacket and insulation layer, with decreasing intensity shown by gradient colors. o Temperature protection of the wooden core, emphasizing the efficacy of insulation and coatings. • Mathematical annotations include Fourier’s law of heat conduction and combined resistance equations. Table 4: Load-Bearing Analysis Brief Description of Drawing: • A 3D exploded view of the composite column, with labeled sections: o Concrete Jacket: illustrated as a protective shell, marked for its compressive strength and large contribution to total load capacity. o Wood Core: Exhibited within the concrete jacket, labeled with its tensile strength and area. o Connections between the layers demonstrating the bonding that ensures effective load sharing. • Force arrows and stress labels for compressive, tensile, and combined loads are included. Examples 1. High-Rise Residential Buildings Fire safety is a critical issue in tall residential buildings due to the rapid spread of fire inside the building structure. A composite wood-reinforced concrete column is an ideal alternative for load walls and vertical supports in such structures. The concrete jacket improves its fire resistance, reducing heat transfer onto the wood in the core by extending the time for residents to leave and for the fire force to react. Besides, the light wood core can alleviate the superposition load of the structural system as a whole, these columns are the practical and safe choice for multi-story apartment buildings. 2. Public Infrastructure in Seismic Zones In areas prone to earthquakes, essential infrastructure like schools, hospitals, and bridges must be built with materials that can endure both seismic forces and fire hazards. The hybrid construct of the composite column provides an efficient load transfer of compressive and tensile forces so that stability is met during earthquakes. Besides, the application of fire- retardant coatings and thermal insulation will offer further protection against fire risks that may occur by the seismically-induced heating process. That makes the composite column a natural choice in critical public infrastructure where safety and robustness are of primary concern. 3. Modular Construction Projects Projects of modular construction using applications such as prefabricated housing and temporary shelters are hampered by weight limits as well as fire resistance. The composite wood-concrete column solves the aforementioned problems providing a lightweight, but strong solution. Prefabricated composite columns are very easy to move and erect, minimizing the time and money used in construction. Fire-resistant properties guarantee compliance with safety regulations and therefore the present columns are especially adapted for modular construction in urban areas or disaster-prone zones, where the need for speed and safety is absolute. Industrial Applicability The Composite Wood-Concrete column is applicable in many sectors. In the construction sector, it can solve fire, load, and eco-sustainability issues, which are very important. The column can be used in homes, commercial places, and public infrastructures. For instance, high-rise residential apartments and office space buildings can get load-bearing columns that are durable and fire-resistant. For example, it can be used in large warehouses and industrial buildings. This is needed where the structure must be durable and fire-resistant. The column can also be used in disaster-resilient infrastructure. For instance, building infrastructure in earthquake-prone as well as wildfire-prone areas can benefit from this composite column. This will reduce risk. The hybrid structure will ensure compressive strength from the concrete and tensile strength from the wood. This will also ensure that the column will not lose its fire-resistant quality yet be stable against any earthquake shocks. Therefore, in construction of emergency shelters, hospitals, evacuation centers, etc. will ensure structural performance. And not just this, it will ensure the safety of people in times of disaster. Due to its lightweight and strong nature, this design is an asset that enhances prefabrication and modular construction. It is easy to transport and put together, saving time and money while building. It is therefore particularly useful for mobile homes and modular industrial buildings. Moreover, it’s used in retrofitting and restoration work of old and historical structures which retains architectural aesthetics without violating safety design.

Claims

Claims Claim 1: A composite wood-concrete column comprising: A center core of wood configured to impart tensile and flexural strength, coated with an intumescent fire-retardant coating that swells in the presence of heat to create a barrier; An external concrete jacket supplemented with the volume of advanced additives, highly focused micro-silica and polypropylene fibers, providing thermal barrier and spalling-resistance along with compressive strength; and A thermal insulation layer between the wooden core and the concrete jacket, made from low-heat conductivity materials is arranged to reduce heat transfer and protect the core against fire exposure. Claim 2: The composite column of claim 1, in which the fire-retardant coating on the wooden core expands under exposure to about 200° C, the coating thereby insulating the interior of the wooden core and preventing direct contact with a flame. Claim 3: The composite column of claim 1, in which the thermal insulation layer is made of silicate boards or geopolymer materials with a thermal conductivity of 0.15 W / m·K or lower and a thickness of 3 mm to 10 mm. Claim 4: The concrete jacket of the composite column of claim 1, including supplementary cementitious materials, fly ash or slag, to improve durability, decrease cracking, and boost environmental sustainability Claim 5: The composite column of claim 1, in which the concrete jacket has a compressive strength of at least 40 MPa and can withstand seismic and dynamic loads. Claim 6: A composite column according to claim 1, in which the wooden core is pre-treated to discourage absorption of moisture and maintain its dimensions, such that under a variety of environmental exposure conditions, the wood and the concrete jacket are compatible. claim 7: The composite column, as designed in Part One, i redesigned to carry a combined load of more than 1.3 MN, such that the concrete encasement will provide compressive support, while thewooden core will undergo tensile forces. claim 8: Claim 1 pertains to a composite column having the design of the invention where heat transfer to the wooden core is limited to no more than 60% of the amount of heat transfer occurring in comparable traditional concrete columns. Claim 9: The composite column of claim 1, in which the lightweight design of the wooden core decreases the overall column weight, increases the natural frequency, and improves performance under seismic conditions. Claim 10: The composite column according to the first claim, where the used materials and the design enable prefabrication of the column allowing modular construction and transport. Claim 11: The composite column of claim 1, further comprises a bonding mechanism, such as mechanical fasteners or adhesives, between the wooden core and the concrete jacket to provide structural integrity. Claim 12: I used the following method to produce the composite column mentioned in the first claim: First, the wooden core is coated with a fire-retardant material. Then, a thermal insulation layer is applied around the wooden core and finally encasing the core and insulating it within a concrete jacket formulated with thermal-resistant additives is done. Claim 13: In the method outlined in claim 12, the concrete is poured and cured under controlled conditions to optimize the bonding between the wooden core, thermal insulation layer, and concrete jacket. The composite column of claim 1 can be utilized in residential, commercial, and public infrastructure projects to increase fire resistance, structural performance, and environmental friendliness. Claim 15: Application of the composite column of claim 1 in upgrading existing buildings, especially the heritage buildings in which the lightweight wooden core acts as a structural member without increasing the building’s weight and at the same time enhances the fire resistance and seismic performance of the structure.

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