Study On The Double-Layer Reciprocal Frame Of Large-span Airport Building

In airport buildings,span and monomer scale are usually very large,and the space structures such as reticulated shell and grid frame are often used as roof structures.However,there are still some problems in the construction process of traditional reticulated shell and lattice structure,and reciprocal frame has unique advantages because of its unique structure form of pair connection between members,which provides a new idea for practical engineering application.However,single-layer reciprocal frame cannot reach large span space due to low stiffness and strength of its members.Therefore,this paper starts with lattice-type members and connections of double-layer reciprocal frame and carries out the following three studies,which are specifically divided into:(1)A lattice-type steel member is presented and a kind of prefabricated connector suitable for the connection between lattice-type steel members are proposed.The mechanical properties of the connectors are analyzed by using the finite element numerical simulation software ABAQUS.The connectors meet the design goal of the strength and rigidity of joints stronger than members.Parameterized analysis is carried out on the prefabricated connector,and the bending stiffness equation of the prefabricated connector has been calculated.The suggested values of each component of the prefabricated connectors are given based on the size of connected lattice-type steel members.(2)Based on the beam element and the connector module,the finite element numerical model of the double-layer hex-tri reciprocal frame of steel is established.According to the geometric extension law of hex-tri grid of reciprocal frame and considering the roof load,the expandability of the double-layer hex-tri reciprocal frame of steel is investigated.The doublelayer hex-tri reciprocal frame of steel can reach the maximum span through twice extension by using the prefabricated connectors and lattice type steel members proposed in this paper.(3)A lattice-type timber member of tenon-mortise is proposed,which can be prefabricated into a double-layer hex-tri timber reciprocal frame of tenon-mortise connection.The material test was carried out and the basic parameters of the test wood material were obtained.The finite element model of double-layer hex-tri timber reciprocal frame of mortise-tenon connection was established by ABAQUS,and the correctness of the finite element model was verified by fullscale test.(4)According to the geometric extension law of hex-tri grid of reciprocal frame,the extension of single-layer and double-layer hex-tri timber reciprocal frame is investigated.Single-layer timber reciprocal frame has low stiffness and low bearing capacity.The singlelayer hex-tri timber reciprocal frame of mortise-tenon connections constituted only by the basic configuration of hex-tri reciprocal frame grid,its stiffness has not met the requirements,so it is more unable to expand to the outside and reach a larger span.In this chapter,the stiffness of the two-layer hex-tri timber reciprocal frame mortise-tenon connections is improved obviously,and the span can be extended twice.