PEB(Pre-Engineered Building) system is a steel portal frame with tapered built up members. The members are tapered to optimize material usage based on the shape of bending moment diagram. It is ideal for low rise long span buildings such as warehouse and factory due to its flexibility for expansion, fast construction, allows large open space and cheaper construction. However, precise design criteria and guidelines are needed because it is composed of non-compact section which can easily buckle under sudden loads.
The PEB system seismic design standards and guidelines are clearly presented in US and Europe. In general, PEB system are classified as steel ordinary moment frames(OMF) and using the response modification factor of 3.5. In Korea, however, it is categorized as general steel structures that are not detailed seismic and uses the R factor of 3.0. It can be seen as conservative that load does not fully reflect the structural performances of PEB system.
To reinforce of PEB connection performance, investigation of state-of-the-art of steel beam-column seismic reinforcement was conducted. As a results, there was three kinds of concept for reinforcing seismic performance of steel beam-column connection. The first is “strengthening section”, the second is “weakening section”, and the last one is “damper”.
Strengthening section types are divided into plate reinforcement, rib reinforcement, panel zone reinforcement, and stiffener reinforcement. It can be increase the performance of connection by reinforcing additional section. Weakening section types are divided into RBS(Reduced Beam Section) and RWS(Reduced Web Section). It is a concept to cut the beam section to serve as a structural damper. Damper types have friction damper and slit damper. Damper is additional device to enhance the seismic performance of the structure.
In this paper, “strengthening section” and “damper” concept are used to enhance the seismic performance of PEB connection to considering safety of the system because PEB system has optimized section already.
Finite element analysis is performed before the experiment to develop the seismic joint reinforcement details of PEB structure system, called π-joint(PI joint) and Brace type joint. π-joint has two types of joint details. One is tapered plate on the inner flange of rafter and column connection and the other is C-plate on the panel zone combined with tapered plate type. Brace type joint has three types of joint details. One is Linear shape brace, another is Uniformly curved shape brace and the other is Variously curved shape brace.
The purpose of this thesis is to develop the seismic reinforcement details for PEB structure system and evaluate the seismic performance of PEB frames under cyclic load. The final goal of this research is to propose PEB system as steel ordinary moment frame system by evaluating response modification factor(R factor).
In this paper, the cyclic loading test is performed with sixteen 3/8 scaled down PEB sub-assemblage frame specimens. The seismic performance of the specimens is evaluated by energy dissipation capacity, strength and response modification factor(R factor). As a result, it could be figured out that PEB system can be categorized as steel ordinary moment frame and π-joint and Brace type joint can enhance the seismic capacity of PEB structure to steel intermediate moment frame.