Portal frame

About: Portal frame is a research topic. Over the lifetime, 1778 publications have been published within this topic receiving 7210 citations.

Inelastic response analysis of reinforced concrete structures using modified force analogy method

Abstract: A modified force analogy method (MFAM) is developed to simulate the nonlinear inelastic response of reinforced concrete (RC) structures. Beam–column elements with three different plastic mechanisms are utilized to simulate inelastic response caused by moment and shear force. A multi-linear hysteretic model is implemented to simulate the nonlinear inelastic response of RC member. The P-Δ effect of the structure is also addressed in MFAM. Static and dynamic inelastic response of structure, damage condition and failure type for structural element, structural limit state and collapse time can also be simulated using MFAM. Compared with the general algorithm, the MFAM provides less computational time especially in the case of large structural system. It is also easier to be written as computer program. Three test data groups, which include cyclic loading test data of a non-ductile RC bridge column, a two-storey RC frame, and dynamic collapse test data of a non-ductile RC portal frame, are selected to confirm the effectiveness of applying MFAM to simulate the inelastic behaviour of structures. Copyright © 2007 John Wiley & Sons, Ltd.

Finite Element Analysis and Tests on Bolted End-Plate Connections in Steel Portal Frames

Abstract: Bolted end-plate connections are being widely used in steel portal frames. In this paper, some tests on beam-to-column and beam-to-beam end-plate connections are reported and the corresponding finite element analysis (FEA) is carried out to analyze their loading resistance and rotational stiffness characteristics. The design method about extended end-plate connections in current design code is discussed, and the necessary improvements are proposed. Especially, some precautions about the classification criterion of the joint stiffness in steel structures are recommended. From the results of comparison, one new model of the bolt tension force distribution and the corresponding design method are presented. It has been verified by the tests that this method can calculate the actual stresses of the bolts and the end-plates more accurately and mobilize their loading capacities more efficiently with sufficient safety and reliability.

A model updating strategy of non‐linear vibrating structures

Abstract: SUMMARY The objective of this paper is to present a model updating strategy of non-linear vibrating structures. Because modal analysis is no longer helpful in non-linear structural dynamics, a special attention is devoted to the features extracted from the proper orthogonal decomposition and one of its non-linear generalizations based on auto-associative neural networks. The efficiency of the proposed procedure is illustrated using simulated data from a three-dimensional portal frame. Copyright 2004 John Wiley & Sons, Ltd.

Full-automatic portal frame stacker crane

Abstract: Disclosed is a full-automatic portal frame stacker crane. The full-automatic portal frame stacker crane comprises stand pillars and a connecting frame arranged at the top ends of the stand pillars, and is characterized in that an X-axis moving mechanism, a Y-axis moving mechanism and a Z-axis moving mechanism are installed on the connecting frame; the X-axis moving mechanism comprises a pair of X-axis sliding rails installed on the opposite sides of the connecting frame; first tackles are connected to the sliding rails through sliding blocks, and are driven by servo motors to freely move on the X-axis sliding rails; the Y-axis moving mechanism comprises a pair of Y-axis sliding rails installed on the first tackles; second tackles are connected to the sliding rails through sliding blocks, and are driven by Y-axis tackles to freely move on the Y-axis sliding rails. The full-automatic portal frame stacker crane has the advantages of being automatically controlled in the whole course without manual intervention, being low in labor intensity, facilitating achieving automated production of enterprises, and being capable of achieving multi-layer stacking of materials, increasing stacking heights and improving working efficiency.

The structural response of industrial portal frame structures in fire.

Abstract: A number of recent fires in single-storey warehouses have drawn attention to a current lack of understanding about the structural response of industrial portal frame structures to elevated temperatures. This research project has investigated the subject by conducting fire tests on a scaled model and by computer modelling using the non-linear finite element program VULCAN. This program has been developed in-house by the University of Sheffield and is capable of modelling the behaviour of three-dimensional steel and composite frames at elevated temperatures. It has been validated throughout its development. An initial investigation was conducted to validate the program for analysing inclined members, which form part of a pitched- roof portal frame, but for which it was not initially developed. Additional features were implemented into the program where necessary. A series of indicative fire tests was conducted at the Health and Safety Laboratories, Buxton. A scaled portal frame model was designed and built, and three major fire tests were conducted in this structure. In the third of these tests the heated rafters experienced a snap-through failure mechanism, in which fire hinges could clearly be identified. The experimental results were then used for validating the numerical results produced by VULCAN analyses. The correlations were relatively close, both for predictions of displacements and failure temperatures. This gave increased confidence in using VULCAN to conduct a series of parametric studies. The parametric studies included two- and three-dimensional analyses, and a number of parameters were investigated, including the effects of vertical and horizontal load, frame geometry, heating profiles and base rotational stiffness. The influence of secondary members was investigated in the three-dimensional studies using different fire scenarios. A simplified calculation method has been developed for estimating the critical temperatures of portal frames in fire. The results compare well with predictions from VULCAN. The current guidance document for portal frames in boundary conditions has been reviewed, and the concept of performance-based design for portal frame structures has been discussed.