Study On Mechanical Properties Of Modular Trestle Structure

Trestle refers to the transport of material on the overhead bridge,which mainly uses belt conveyer equipments.In recent years,the amount of coal trestle construction gradually increases and the span of coal trestle is getting larger and larger.However,there are some shortcomings in the traditional steel trestle,the design method of which needs to be further optimized.Nowadays,modular trestles have been widely used in countries such as Australia,but due to the technical level of industry,they are not widely used in coal transportation.This research is to study the mechanical properties of modular trestle structure,so that it can meet the design requirements of steel trestles in China.The main structure of the modular trestle is composed of the top stringer(angle steel),the thin-walled corrugated sheet,the bottom stringer(channel steel),the ribs,the top crossbeam(channel steel)and the bottom crossbeam(channel steel).The semi-enclosed steel structures built by steel can be divided into single-belt trestles and double-belt trestles.In this paper,firstly,the shell element model is established by finite element analysis(FEA)software SAP2000 to study and analyse the mechanical properties of the whole structure.Then,based on the results of FEA,a simplified analysis method of modular trestle is proposed.Taking the 1.4m single-belt trestle as an example,the preliminary section of each member is obtained,and the relevant bearing capacity test of the full-scale model is carried out,which will be compared with the results of FEA.1)The results of FEA show that the structure of modular trestle is complicated and the overall performance is like a simply supported beam within bending state.The top part is under pressure and the bottom part is in tension.The top and bottom stringers function as flanges,and the corrugated sheets function as webs.The ribs are mainly used for connection and support,of which the stress is much smaller.The horizontal wind load has little effect on the whole structure,and the vertical load plays the controlling role.2)The thin-walled corrugated sheets can be used as the bearing member of the structure under the support of the ribs,which is one of the innovations of this new kind of modular trestle.Compared with traditional steel trestle,modular trestle removes the complicated support members,which can save the amount of steel materials,and make the structure of modular trestle more economical.3)Based on the mechanical properties of modular trestle’s structure and members by FEA,several simplified methods for the primary cross-section selection of this new modular trestle’s members are designed.The calculation steps of how to obtain the primary cross-section of each main member are obtained.Also,the test is consistent with the results of FEA,which proves that the structure of modular trestle has a large bearing capacity,and is safe and reliable.According to the primary selection method of the member section,the main member section selection table belonging to the modular trestle is designed to form the stereotyped product,which can provide design references for projects that are also novel in structure and complex in three-dimensional models.