Composite Reinforced Concrete

Composite reinforced concrete Composite reinforced concrete R.TAYLOR B S c , DIC, MICE, MIStructE Senior Lecturer in Civil Engineering University of Manchester Simon Engineering Laboratories Thomas Telford Limited, London, 1979 Published by Thomas Telford Limited, Telford House, PO Box 101, 2 6 - 3 4 Old Street, London EC1P 1JH ISBN: 0 7277 0077 4 © R. Taylor, 1979 All rights, including translation, reserved. Except for fair copying, no part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means electronic, mechanical, photocopying, recording or otherwise, without the prior written permission of the Managing Editor, Publications Division, Institution of Civil Engineers, PO Box 101, 2 6 - 3 4 Old Street, London EC1P 1JH Typeset and printed by Henry Ling Limited, Dorchester FOREWORD There is no doubt that none of the major structural materials is ideal. Despite the long-standing use of various combinations of steel and concrete, all methods of combining these materials have some draw­ backs. While ordinary reinforced concrete combines the use of the tensile strength of steel with the compressive strength of concrete, it cannot take full advantage of high tensile steels because of the limited capacity of concrete to undergo tensile strain without excessive crack­ ing. Although this problem is overcome in prestressed concrete, the economy resulting from the use of ultra-high strength steels is offset by the costly prestressing operation, at least for site construction. The other main traditional steel—concrete combination — composite con­ struction — has undoubted advantages in construction but is extravagant in its use of steel. It would be advantageous if the economic use of ultra high strength tensile steel could be combined with the convenience of composite construction. While composite reinforced concrete does not completely achieve this ideal, it goes some way towards it. The Author of this monograph, Mr R. Taylor, has developed his pro­ posals for composite reinforced concrete as a result of pursuing two other lines of research. The first arose from the aim of improving the efficiency of the use of steel in composite construction by incorporating deep haunches in the beams without sacrificing constructional advan­ tages. In the second investigation, Mr Taylor sought a means of improving the exploitation of reinforced concrete beyond the limits currently recommended by Codes of Practice. As a result of these two investigations, it was realized that the incorporation of deep haunches in composite beams could be achieved alongside the use of high tensile reinforcement to give a possible improvement in overall economy. It is hardly likely that innovatory methods of construction will be accepted unless they show distinct advantages. Composite reinforced concrete may well have such advantages in multi-storey structures when it is desired to use precast flooring units in conjunction with an in situ concrete frame in which the beams need to be of minimum construc­ tional depth. The present monograph is published with the intention of stimulating practical exploration of this proposed method of construction. Con­ siderable theoretical economies are possible; the realization of these economies in practice could lead to major steps forward in the more economic exploitation of steel—concrete composite construction. M. R. Home Manchester March 1979 PREFACE This research monograph on composite reinforced concrete is based on lectures given at a research seminar in April 1979 at the Simon Engineering Laboratories of the University of Manchester. At this stage composite reinforced concrete is only a research material and has not been used in practice. Indeed hitherto it has not been possible to use composite reinforced concrete as there has