The structure in this design example is an eight-story office with load-bearing reinforced concrete walls as its seismic-force-resisting system. This design. 7 Examples of Densely Reinforced Concrete Structures. Reinforced Concrete Column. Reinforced Concrete Wall. Cover Page i Reinforced Concrete Design Theory and Examples Page ii Other Design of reinforced concrete walls Wall reinforcement
Enquiries concerning reproduction outside the terms stated here should be sent to the publishers at the London address printed on this page. The publisher makes no representation, express of implied, with regard to the accuracy of the information contained in this book and cannot accept any legal responsibility or liability for any errors or omissions that may be made. Approximate method from CP 9. The aim remains as stated in the first edition: to set out design theory and illustrate the practical applications by the inclusion of as many useful examples as possible.
The book is written primarily for students on civil engineering degree courses to assist them to understand the principles of element design and the procedures for the design of concrete buildings. The book has been extensively rewritten. A chapter has been added on materials and durability. Other chapters such as those on columns and buildings have been extended and the design of walls in buildings has been given a separate chapter. A special chapter on the analysis and design of very tall buildings has also been added.
This should give students an appreciation of the way in which these buildings are modelled for computer analyses and the design problems involved.
The importance of computers in structural design is recognized. Computer programs for design of concrete elements are included. In these sections, the principles and steps involved in the construction of the programs are explained and the listings are given. Page xviii This page intentionally left blank. Page xx This page intentionally left blank. Page 1 1 Introduction 1.
Its virtue is its versatility, i. It is also very durable and fire resistant when specification and construction procedures are correct. Concrete can be used for all standard buildings both single storey and multistorey and for containment and retaining structures and bridges.
Some of the common building structures are shown in Fig. The single-storey portal supported on isolated footings; 2. The medium-rise framed structure which may be braced by shear walls or unbraced. The building may be supported on isolated footings, strip foundations or a raft; 3.
The tall multistorey frame and core structure where the core and rigid frames together resist wind loads. The building is usually supported on a raft which in turn may bear directly on the ground or be carried on piles or caissons. These buildings usually include a basement. Complete designs for types 1 and 2 are given. The analysis and design for type 3 is discussed. The design of all building elements and isolated foundations is described. Page 3 excessive settlement.
Alternatively the bases may be supported on piles. To learn concrete design it is necessary to start by carrying out the design of separate elements.
However, it is important to recognize the function of the element in the complete structure and that the complete structure or part of it needs to be analysed to obtain actions for design. The elements listed above are illustrated in Fig. A cast-in-situ framed reinforced concrete building and the rigid frames and elements into which it is idealized for analysis and design are shown in Fig. The design with regard to this building will cover 1.
A one-way floor slab supported on primary reinforced concrete frames and secondary continuous flanged beams is shown in Fig. In Fig.
Flat slab construction, where the slab is supported by the columns without beams, is also described. Structural design for isolated pad, strip and combined and piled foundations and retaining walls Fig. Construction in different materials and with different arrangements and systems may require investigation to determine the most economical answer. Architect and engineer should work together at this conceptual design stage. Once the building form and structural arrangement have been finalized the design problem consists of the following: 1.
Page 5 Fig.
Page 6 Fig. A thorough knowledge of the codes is one of the essential requirements of a designer. Thus it is important that copies of these codes are obtained and read in conjunction with the book. Generally, only those parts of clauses and tables are quoted which are relevant to the particular problem, and the reader should consult the full text.
Only the main codes involved have been mentioned above. Other codes, to which reference is necessary, will be noted as required. They are needed to determine the loading on the elements and structure and to carry out the analysis and design of the elements. The examples in the book do not precisely follow this procedure because they are set out to explain in detail the steps in design. The need for orderly and concise presentation of calculations cannot be emphasized too strongly.
These aids make exact design methods easier to apply, shorten design time and lessen the possibility of making errors. Part 3 of BS consists of design charts for beams and columns, and the construction of charts is set out in this book, together with representative examples. The use of computers for the analysis and design of structures is standard practice.
In analysis exact and approximate manual methods are set out but computer analysis is used where appropriate.
Computer programs for element design are included in the book. However, it is essential that students understand the design principles involved and are able to make manual design calculations before using computer programs. The structural requirements for the individual elements are presented in the detail drawings. Detailing translates this information into a suitable pattern of reinforcement for the structure as a whole.
It is essential for the student to know the conventions for making reinforced concrete drawings such as scales, methods for specifying bars, links, fabric, cut-off points etc. The main particulars for detailing are given for most of the worked exercises in the book. The bar schedule can be prepared on completion of the detail drawings.
Computer detailing suites are now in general use in design offices. Students should be given practice in using the software during their degree course. Page 9 2 Materials, structural failures and durability 2. Concrete is itself a composite material. The dry mix consists of cement and coarse and fine aggregate. Water is added and this reacts with the cement which hardens and binds the aggregates into the concrete matrix; the concrete matrix sticks or bonds onto the reinforcing bars.
The properties of the constituents used in making concrete, mix design and the principal properties of concrete are discussed briefly. A knowledge of the properties and an understanding of the behaviour of concrete is an important factor in the design process. The types and characteristics of reinforcing steels are noted.
Deterioration of and failures in concrete structures are now of wide-spread concern. This is reflected in the increased prominence given in the new concrete code BS to the durability of concrete structures. The types of failure that occur in concrete structures are listed and described. Finally the provisions regarding the durability of concrete structures noted in the code and the requirements for cover to prevent corrosion of the reinforcement and provide fire resistance are set out.
The raw materials from which it is made are lime, silica, alumina and iron oxide. These constituents are crushed and blended in the correct proportions and burnt in a rotary kiln. The clinker is cooled, mixed with gypsum and ground to a fine powder to give cement.
The main chemical compounds in cement are calcium silicates and aluminates. When water is added to cement and the constituents are mixed to form cement paste, chemical reactions occur and the mix becomes stiffer with time and sets.
This ensures that the concrete does not set too quickly before it can be placed or too slowly so as to hold up construction. Two stages in the setting process are defined in BS Specification for Ordinary and Rapid Hardening Portland Cement These are an initial setting time which must be a minimum of 45 min and a final set which must take place in 10 h.
Cement must be sound, i. Tests are specified in BS12 for soundness and strength of cement mortar cubes. Many other types of cement are available some of which are 1. Aggregate is classed into the following two sizes: 1. Aggregates should be chemically inert, clean, hard and durable. Organic impurities can affect the hydration of cement and the bond between the cement and the aggregate.