In the field of architecture, trusses serve as a crucial component of buildings, much like the human skeleton, shouldering the important tasks of support and stability. The choice of material directly impacts the safety and durability of a building. Traditionally, wood has been a commonly used material for constructing trusses due to its ease of access and processing. Throughout the long history of architecture, countless classic wooden truss buildings have been created. However, with the rapid advancement of construction technology and the increasing demands for functionality and durability in modern architecture, steel has gradually emerged as a strong alternative to wood. Steel trusses, with their unique advantages, play an irreplaceable role in numerous construction scenarios.
Steel trusses have an extremely wide range of applications. In the realm of industrial construction, for large-scale factories, industrial park buildings, and other structures with steel frames, steel trusses seamlessly integrate with the overall steel frame structure. Through precise node connections and mechanical design, they ensure that the entire building remains stable and reliable even when subjected to heavy loads and complex stress, making them the top choice for such buildings. In residential building roof reconstruction projects, especially when converting flat roofs into pitched roofs, lightweight steel trusses demonstrate significant advantages. They are relatively light in weight, causing minimal stress on existing building structures such as walls and ceilings. During the construction process, they can minimize damage to the original building structure while effectively enhancing the roof’s drainage performance and space utilization. In large public buildings, such as supermarkets, aircraft hangars, and warehouses with large – span structures, steel trusses are extremely common. Take large airport hangars as an example; they require a spacious column – free interior to accommodate various large aircraft. Steel trusses, with their excellent mechanical properties and large – span load – bearing capacity, can easily create column – free spaces spanning tens or even hundreds of meters, meeting special functional requirements.
In terms of working principles, steel trusses are similar to most steel structures. In the design stage, engineers utilize advanced computer – aided design (CAD) and finite element analysis (FEA) software to conduct precise mechanical calculations and structural optimization designs for steel trusses based on factors such as the building’s usage function, load requirements, and seismic grade. Subsequently, steel trusses are purchased in finished form and can be customized according to all necessary design options and modifications. During the production process, advanced processes such as automated cutting and welding are employed to ensure the dimensional accuracy and quality stability of steel components. Installation is usually provided by the company that originally produced these structural components. They first manufacture steel trusses in a semi – assembled form. This modular production method not only improves production efficiency but also facilitates transportation and on – site installation. After being transported to the site, experienced construction teams assemble all components precisely according to strict installation procedures, using professional hoisting equipment and connection techniques. Through methods such as high – strength bolt connections or welding, the steel trusses form a solid integral structure.
Compared with traditional wooden trusses, steel trusses exhibit unique characteristics in many aspects. In terms of price, although steel was once considered expensive due to high smelting and processing costs, with the continuous innovation of modern steel – making technologies, such as the widespread application of electric arc furnace steel – making technology, the popularization of continuous casting and rolling processes, and the economies of scale brought about by large – scale industrial production, the price of steel has gradually decreased, and its cost – effectiveness has become increasingly prominent. Wood, as a natural material, has always been a relatively inexpensive building material. However, it is highly affected by various factors, including growth cycles, forest resource protection policies, natural disasters (such as forest fires and pest disasters), and market supply and demand. For example, when a region experiences a severe forest pest infestation resulting in a significant reduction in timber production, the price of ordinary wooden roof trusses in that area may increase significantly in a short period, posing cost risks to construction projects.
Regarding the types of buildings they are suitable for, strength, and lifespan, wood, due to its relatively light texture and ease of processing, is more suitable for various relatively small residential buildings, such as home warehouses and single – family houses, meeting the requirements of these buildings for lightweight structures and convenient construction. However, steel, as a high – strength industrial material, has a much higher strength – to – weight ratio than wood. For instance, the yield strength of common Q345 steel can reach 345MPa, while the compressive strength of ordinary wood is only dozens of MPa. This high – strength characteristic enables steel trusses to achieve thinner and lighter component designs while ensuring structural safety, effectively reducing the self – weight of the building. Additionally, the expected service life of steel trusses is 50 to 70 years. Under normal use and reasonable maintenance, they require almost no frequent repairs or replacements. In contrast, limited by the natural properties of wood, the maximum service life of wooden trusses is only 30 years. During use, they are prone to a decline in structural performance due to problems such as moisture absorption and mildew, and require regular anti – corrosion and anti – insect treatments, resulting in higher maintenance costs.
Both steel and wood, as materials, have their own weaknesses. Due to its organic nature, wood is susceptible to environmental humidity and temperature. It is prone to decay in humid environments and can be eroded by pests such as termites. Once decay or pest infestation occurs, it will seriously affect the structural strength and stability of wooden trusses. Although steel has good mechanical properties, it is vulnerable to high temperatures. When the temperature reaches around 400°C, the strength of steel will decrease significantly. In high – temperature environments such as fires, if steel – structured buildings do not have effective fire protection measures, they may lose their load – bearing capacity in a short period, leading to building collapse. However, due to its natural heat – insulation properties, wood usually has a certain degree of fire resistance and heat resistance. After fire – proof treatment, the fire resistance of wood can be further enhanced. Steel, with its stable chemical properties, is resistant to both decay and pests. In harsh environments such as humid and highly corrosive conditions, it has more advantages compared to wood.
In terms of installation speed, compared with wood, the overall installation of steel structures is slightly more difficult due to higher requirements for construction technology and precision. For example, during the bolt connection of steel trusses, the tightening torque of bolts needs to be strictly controlled to ensure connection reliability. In the welding process, the quality of welds must be guaranteed to avoid defects such as porosity and slag inclusions. However, for professional installation teams, with their rich construction experience and advanced construction equipment, this difference can be minimized. Moreover, since steel structures can be prefabricated in the factory, most components can be manufactured off – site, and only assembly and connection are required on – site. This reduces on – site construction workload and construction cycles, making transportation and installation easier. In some large – scale construction projects, the prefabrication and installation method of steel trusses can shorten the construction period by 30% – 50%, greatly improving project construction efficiency.
In terms of recyclability, steel is a completely recyclable material, and steel trusses are no exception. When a building reaches the end of its service life or needs to be demolished and rebuilt, the components of steel trusses can be completely disassembled. After simple processing, they can be remelted in a furnace and made into various steel products, realizing the recycling of resources. This not only reduces the generation of construction waste but also decreases the consumption of natural resources. In contrast, wood can only be recycled when it is clean and uncontaminated. Once wooden components are painted, stained, or contaminated by chemicals, mold, etc., due to the high difficulty and cost of processing, they are usually treated as waste and cannot be effectively recycled, which causes a certain degree of resource waste.
Steel trusses, with their advantages in performance, cost, environmental protection, and other aspects, occupy an important position in modern architecture. Despite their shortcomings, such as vulnerability to high temperatures, with the continuous development of fire – proof coating technology, the application of new fire – protection measures for steel structures, and the continuous innovation of construction technology, the application prospects of steel trusses will surely be broader. They will bring more possibilities and development opportunities to the construction industry, promoting the construction industry to move towards a more secure, efficient, and environmentally friendly future.
