【Beginner in Static Equipment】What are strong columns and weak columns in steel structures?
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Today I came across a news report mentioning the strong columns and weak columns in steel structures. The installation of the steel structure for the petroleum coke hydrogenation unit at Guangdong Petrochemical has begun. At 8:58 a.m. on October 29th, at the signal given by the crane operator, two cranes with capacities of 80 tons and 25 tons slowly lifted the steel structure belonging to the first axis of the process and heating pipelines, thus marking the official start of the ground installation work for the petroleum coke hydrogenation unit at Guangdong Petrochemical’s POX project department. The project department attaches great importance to the commencement of the installation work; it holds special meetings to outline the requirements regarding technical preparation, construction preparations, safety, and quality, and carefully selects construction teams with strong capabilities. All departments involved in the project organized themselves meticulously and collaborated closely to carry out extensive preparatory work for the start of installation. Before construction, the work team received specialized safety and technical briefings; during construction, strict control was exercised over alignment accuracy and welding quality to ensure the smooth installation of the steel structure. The total weight of the steel structure for the process and heating external pipes is 1,380 tons. Welding is primarily used for the strong axes, while bolting is mainly employed for the weak axes. The drawings available so far cover axes 1 to 38; the structural foundation is of the cup-shaped type, which **increases the technical complexity of installing the steel structure. However, thanks to thorough preparatory work prior to construction, the installation was carried out smoothly. During the installation process, the installation of beams and associated structures is carried out using straight-arm lift trucks, with scaffolding being used as little as possible; this not only speeds up the installation progress but also reduces construction costs. What are strong columns and weak columns in steel structures? Why is the design done this way here? ? Welcome to join the discussion – HaiChuan is more exciting with you here
Information found online ==================== Using stronger columns and weaker beams is intended to improve seismic resistance; from an energy perspective, stronger columns and weaker beams allow for better absorption of seismic energy； When an earthquake occurs, we hope that plastic hinges will form at both ends of the beam in order to absorb seismic energy; if the vertical members yield first, the situation becomes serious! The concept of strong columns and weak beams is related to earthquake resistance; during an earthquake, the beams should fail before the columns, as columns, being vertical load-bearing elements, are more important than beams. The failure of a few beams generally only causes things like the collapse of floor slabs; if one column fails, the load distributed on the adjacent columns increases, making it likely that they too will fail. This can lead to the collapse of the entire structure, which is very dangerous. That’s why this concept is emphasized. This concept is generally known by those working in the field of structural design, but in practice many people don’t consider it; they tend to increase the reinforcement in the beams and enlarge the cross-sections, thinking this makes things safer. In fact, this can sometimes result in beams that are stronger than the columns, which is even less safe. I don’t like adding extra rebar, unless it’s for cantilevered elements. The codes also contain certain provisions, such as Article 6.2.2 of the seismic code
Therefore, the statement that welding is used primarily for the strong axis and bolting is used primarily for the weak axis is not accurate. A more precise description would be that welding is used primarily in the direction of the strong axis, while bolting is used primarily in the direction of the weak axis. It’s still the same column; only the direction and strength differ