-

Precast Concrete Structures, Second Edition Kim S. Elliott

Precast Concrete Structures, Second Edition

Kim S. Elliott

A precast concrete structure is an assemblage of precast elements which, when suitably connected together, form a three-dimensional framework capable of resisting gravitation and wind (or even earthquake*) loads.

The framework is ideally suited to buildings such as offices, retail units, car parks, schools, stadia, and other such buildings requiring minimal internal obstruction and multifunctional leasable space. The quantity of concrete in a precast framework is less than 4% of the gross volume of the building, and two-thirds of this is in the floors. In the case of the shopping centre and car park shown in Figure 1.6, the precast concrete elements supporting vertical actions (i.e. gravity loads) are columns, beams, floor slabs, staircases, and stair-cores.

The framework is ‘braced’ against horizontal actions (i.e. lateral loads and wind pressure) using very deep columns (gable end to the left of the photo) and diagonal bracing (front elevation). The framework shown in Figure 1.7 was built using similar elements, but because the resistance against horizontal actions is provided by the same columns that support vertical actions, the framework and hence the columns are classed as ‘unbraced’.

The precast framework Figure 1.8 is likewise a column, beam and slab structure, but here the beam-to-column connections are designed as moment resisting, and therefore together with the strength and stiffness of the beams and columns, the resistance against horizontal actions is provided frame action, in a similar manner as for cast in-situ concrete frames.

The distinguishing feature of the precast framework is that the beam-to-column connections are rarely fully rigid, known as ‘semi-rigid’, and therefore the columns must also resist horizontal actions as in the case of the unbraced frame in Figure 1.7. The frameworks shown in Figures 1.9 and 1.10 were built using similar elements, but thanks to some creative surface finishes and more expensive mouldings, this building appears to have a completely different function, both architecturally and structurally.

Content :

What is precast concrete
Materials used in precast structures
Precast frame analysis
Precast concrete floors
Precast concrete beams
Precast concrete columns
Shear walls
Horizontal floor diaphragms
Joints and connections
Joints and connections
Beam and column connections
Ties in precast concrete structures
Design exercise for 10-storey precast skeletal frame

Download Link

Concrete Construction Engineering Handbook

Portland cement concrete is a composite material made by combining cement, supplementary cementing materials, aggregates, water, and chemical admixtures in suitable proportions and allowing the resulting mixture to set and harden over time.

Because hardened concrete is a relatively brittle material with a low tensile strength,

strength, steel reinforcing bars and sometimes discontinuous fibers are used in structural concrete to provide some tensile load-bearing capacity and to increase the toughness of the material.

In this chapter, we deal with some of the basic constituents: cements, aggregates, water, steel reinforcement, and fiber reinforcement.

Chemical admixtures and supplementary cementing materials (often referred to as mineral admixtures) are covered in Chapter 2.

It must be emphasized that choosing the appropriate

[su_button url=”https://drive.google.com/open?id=13ms52JNDq6M-jVYj2QGpt9RT1MTPMggU” size=”7″ center=”yes”] Download Link[/su_button]

Dictionary of Construction Terms

This Dictionary of Construction Terms is intended to cover a wide range of the more common as well more esoteric yet important terms a building professional,

lawyer, student, judge, arbitrator, adjudicator, engineering economist or the like may require defi nition upon in the construction law fi eld.

The intention is to clear the fog, and to do so concisely in clear English in an alphabetical format.

So whether you are looking for the answer to a spandrel panel, chequerplate, revetment,

or NAECI or what is meant by nemo dat quod non habet or the rule in Pinnel’s case, we have it here, and a whole lot more.

In about 1994 I started assembling a construction database on my Psion Organiser

(for those that can remember such pocket computers) regularly adding building and engineering terms,

legal references etc relevant to the fi rm’s work as construction lawyers.

I was always excited to learn new terms and add to the record. Then about 10 years ago with the advent of powerful networked computing and software systems,

Fenwick Elliott created its own intranet platform, and that database was uploaded toit.

It was coined by the offi ce, “Simon Says”.

This data rapidly grew with our busy international practice and with projects

that are more complex the legal issues thrown up blossomed in tandem with the new technologies.

[su_button url=”https://drive.google.com/open?id=1IY3NMG58plXDIXwY02gBA6vUTQql9bTM” size=”7″ center=”yes”] Download Link[/su_button]

Formwork a Practical Guide

Amongst the many trades on a typical building site, the role and responsibilities of the formworker are unique.

There are few restrictions placed on his choice of working techniques.

In contrast, other trades are constrained by the most precise directions.

For the structural steelwork all sizes, connections, fixings and painting are defined in detail.

Reinforcement grades, sizes, positions, laps and tolerances are all predetermined.

Joinery is exhaustively detailed, colour schemes are prescribed, and furnishings selected.

Compared to this, the formworker is almost permitted to be a free spirit.

Most times, the only constraints are mandatory requirements on the concrete surface quality and accuracy, together with the builder’s demands on cost and time.

Outside this, he chooses his own formwork system, selects his materials and components, and devises the general arrangement and the details of construction.

Three general principles govern formwork design and construction:

QUALITY
SAFETY
ECONOMY.

These three matters are not separate and unrelated. Experienced formworkers know that it is a false economy to reduce quality.

Further, if the formworker feels safe, this will lead to more production and thus reduced costs.

Throughout this book, even if they are not specifically mentioned, these three principles are fundamental to all the matters described.

In this chapter their further discussion will relate ‘Quality’ to the quality of the concrete structure being produced, ‘Safety’ to both personal safety and formwork loading,

and ‘Economy’ to the matters that affect the total effective cost of formwork and the contribution of this to the total cost of the concrete structure.

The activity of formwork construction, its concreting and subsequent stripping, can
also have a significant loading effect on the permanent concrete structure being built.

The design engineer for the permanent structure may place restrictions on the formworkers activities.

The formworker must ensure that full INFORMATION has been supplied on these and any other requirements that will influence the materials, methods of use and quality of the formwork.

[su_button url=”https://drive.google.com/open?id=1NYyjbzyjP7m8avDnHrRcW84L9wkHVJ0a” size=”7″ center=”yes”] Download Link[/su_button]

FRP Composites for Reinforced and Prestressed Concrete Structures

Fiber-reinforced polymer (FRP) is a common term used by the civil engineering community for high-strength composites.

Composites have been used by the space and aerospace communities for over six decades and the use of composites by the civil engineering community spans about three decades.

In the composite system, the strength and the stiffness are primarily derived from fibers, and the matrix binds the fibers together to form structural and nonstructural components.

Composites are known for their
high specific strength, high stiffness, and corrosion resistance.

Repair and retrofit are still the predominant areas where FRPs are used in the civil engineering community.

The field is relatively young and, therefore, there is considerable ongoing research in this area.
American Concrete Institute Technical Committee 440 documents are excellent sources
for the latest information.

The primary purpose of this book is to introduce the reader to the basic concepts of repairing and retrofitting reinforced and prestressed concrete structural elements using FRP.

Basic material properties, fabrication techniques, design concepts for strengthening in bending, shear, and confinement, and field evaluation techniques are presented.

The book is geared toward advanced undergraduate and graduate students, professional engineers, field engineers, and user agencies such as various departments of transportation.

A number of flowcharts and design examples are provided to facilitate easy and thorough understanding.

Since this is a very active research field, some of the latest techniques such as near

-surface mounting (NSM) techniques are not covered in this book.

Rather, the aim is to provide the fundamentals and basic information.

[su_button url=”https://drive.google.com/open?id=1uzqDFd8GwF3Vb-wpphrQ6tkG4mw_WdB6″ size=”7″ center=”yes”] Download Link[/su_button]

Failures in Concrete Structures

Many failures, when investigated, have been found to arise from a combination of causes.

The traditional design sequence starts with the sizing of members.

These are determined from the loading (permanent and variable actions) with reference to bending moments and, for beams, shear forces.

The reinforcement is then calculated to cater for these forces.

Much of the reinforcement is detailed only after completion of the contract documents.

Later, if problems are found in fitting the required reinforcement into an element or joint, it is difficult to change the size of section on which the architect and services engineers agreed.

Many such problems could have been avoided by producing sketches early on to show how the joint details could work before sizes were finalised.

This book is a personal selection of incidents that have occurred related to reinforced and prestressed concrete structures.

Not all have led to failures and some of the mistakes were discovered at the design stage.

Each incident required some form of remedial action to ensure safety of the structure.

Some of the incidents were caused by mistakes in design or construction or both.

Some involved collapse of part of the structure, but in such cases the cause was from mor than one unrelated mistake or problem.

A few of the errors and incidents were caused by deliberate intent.

Chapters 1 to 11 describe specific incidents such as structural misunder standing, extrapolation of codes of practice, detailing, poor construction, and other factors.

When a particular incident involved more than one of these causes, it is described in the most relevant section.

Chapters 12 and 13 discuss issues related to procurement and research and development.

[su_button url=”https://drive.google.com/open?id=105HfRaX-HQoBy-MfAQKgYHYBmki2xn0P” size=”7″ center=”yes”] Download Link[/su_button]