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CONTENTS
Volume 3, Number 3, June 2003
 

Abstract
This paper discusses the results and observations from a large-scale fire test conducted on a slim floor system, comprising asymmetric beams, rectangular hollow section beams and a composite floor slab. The structure was subjected to a fire where the fire load (combustible material) was higher that that found in typical office buildings and the ventilation area was artificially controlled during the test. Although the fire behaviour was not realistic it was designed to follow as closely as possible the time-temperature response used in standard fire tests, which are used to assess individual structural members and forms the bases of current fire design methods. The presented test results are limited, due to the malfunction of the instrumentation measuring the atmosphere and member temperatures. The lack of test data hinders the presentation of definitive conclusions. However, the available data, together with observations from the test, provides for the first time a useful insight into the behaviour of the slim floor system in its entirety. Analysis of the test results show that the behaviour of the beam-to-column connections had a significant impact on the overall structural response of the system, particularly when the end-plate of one of the connections fractured, during the fire.

Key Words
fire test; asymmetric beams; slim floor; structural behaviour; elevated temperatures; con-nections; composite slab.

Address
Manchester Centre for Civil and Construction Engineering, The University of Manchester, PO Box 88, Manchester, M60 1QD, UK

Abstract
This paper presents a generic modelling of composite steel-concrete beams with elastic shearrnconnection. It builds on the well-known seminal technique of Newmark, Siess and Viest, in order tornformulate the partial interaction formulation for solution under a variety of end conditions, and lends itself well for modification to enable direct quantification of effects such as shrinkage, creep, and limited shear connection slip capacity. This application is possible because the governing differential equations are set up and solved in a fashion whereby inclusion of the kinematic and static end conditions merely requires a statement of the appropriate constants of integration that are generated in the solution of the linear differential equations. The method is applied in the paper for the solution of the well-studied behaviour of simply supported beams with partial interaction, as well as to provide solutions for a beam encastr? at its ends, and for a propped cantilever.

Key Words
composite beams; differential equations; elasticity; indeterminate; interface slip; partial interaction.

Address
School of Civil and Environmental Engineering, The University of New South Wales, UNSW, Sydney, NSW 2052, AustraliarnSchool of Civil and Environmental Engineering, The University of New South Wales, UNSW, Sydney, NSW 2052, AustraliarnSchool of Civil and Environmental Engineering, The University of New South Wales, UNSW, Sydney, NSW 2052, Australia

Abstract
The concept of performance based seismic design has been gradually accepted by thernearthquake engineering profession recently, in which the cost-effectiveness criterion is one of the mostrnimportant principles and more attention is paid to the structural performance at the inelastic stage. Since there are many uncertainties in seismic design, reliability analysis is a major task in performance based seismic design. However, structural reliability analysis may be very costly and time consuming because the limit state function is usually a highly nonlinear implicit function with respect to the basic design variables, especially for the complex large-scale structures for dynamic and nonlinear analysis. Understanding statistical properties of the structural inelastic deformation, which is the aim of the present paper, is helpful to develop an efficient approximate approach of reliability analysis. The present paper studies the statistical properties of the maximum elastoplastic story drift of steel frames subjected to earthquake load. The randomness of earthquake load, dead load, live load, steel elastic modulus, yield strength and structural member dimensions are considered. Possible probability distributions for the maximum story are evaluated using K-S test. The results show that the choice of the probability distribution for the maximum elastoplastic story drift of steel frames is related to the mean value of the maximum elastoplastic story drift. When the mean drift is small (less than 0.3%), an extreme value type I distribution is the best choice. However, for large drifts (more than 0.35%), an extreme value type II distribution is best.

Key Words
steel frames; elastoplastic analysis; seismic design; probability distribution; K-S test.

Address
Department of Engineering Mechanics, State Key Laboratory of Structural Analysis of Industrial Equipment, Dalian University of Technology, Dalian, 116024, China

Abstract
An experimental investigation of lightweight aggregate and foamed concrete contribution to the ultimate strength capacity of square and rectangular steel tube sections is presented in this study. Thirty-four simply supported beam specimens, 1000-mm long, filled with lightweight aggregate and foamed concretes were tested in pure flexural bending to calculate the ultimate moment capacity. Normal concrete-filled steel tubular and bare steel sections of identical dimensions were also tested and compared to the filled steel sections. Theoretical values of ultimate moment capacity of the beam specimens were also calculated in this study for comparison purposes. The test results showed that lightweight aggregate and foamed concrete significantly enhance the load carrying capacity of steel tubular sections. Furthermore, it can be concluded from this study that lightweight aggregate and foamed concretes can be used in composite construction to increase the flexural capacity of the steel tubular sections.

Key Words
ultimate moment; composite section; lightweight concrete; foamed concrete; concrete contribution factor.

Address
Department of Civil Engineering, Al-Isra University, Amman 11191, P.O. Box (910277), JordanrnDepartment of Civil Engineering, University of Jordan, JordanrnDepartment of Civil Engineering, University of Jordan, Jordan

Abstract
A high precision shear deformable triangular element has been proposed for free vibrationrnanalysis of composite trapezoidal plates. The element has twelve nodes at the three sides and four nodes inside the element. Initially the element has fifty-five degrees of freedom, which has been reduced to forty-eight by eliminating the degrees of freedom of the internal nodes through static condensation. Plates having different side ratios (b/a), boundary conditions, thickness ratios (h/a=0.01, 0.1 and 0.2), number of layers and fibre angle orientations have been analyzed by the proposed shear locking free element. Trapezoidal laminate with concentrated mass at the centre has also been analyzed. An efficient mass lumping scheme has been recommended, where the effect of rotary inertia has been included. For validation of the present element and formulation few results of isotropic trapezoidal plate and square composite laminate have been compared with those obtained from open literatures. The numerical results for composite trapezoidal laminate have been given as new results.

Key Words
finite element; shear-locking free element; composite trapezoidal plate; rotary inertia; first order shear deformation theory; lump mass.

Address
Department of Applied Mechanics, B. E. College (D. U.), Howrah-7111 03, lndia


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