PRECAST COMPOUND WALL

BY : HARSH G. BOTHRA Roll No.: 3141060Under the Guidance of Prof: M. M. MAKWANA Department of Civil Engineering, MITCOE PUNE

Introduction

The precast concrete compound-wall panel has been used in Europe for decades.

The original compound-wall design consisted of two types of reinforced concrete and of plain concrete.

Compound (Boundary) walls include privacy walls, boundary-marking walls on property, and town walls.

Characteristics

Precast concrete was developed by combining the best aspects of two familiar technologies: the durability, fast erection, and architectural versatility of precast concrete and the light weight and high strength of panelised cold-formed steel stud framing.

The strength-to-weight ratio is high. The precast units can support their own weight and be lifted off the

casting tables only 24 hours after casting, making cycle-time short and efficient.

Large panel sizes are practical to cast and light enough to handle with lighter equipment, resulting in fewer panels to erect and fewer panel joints to seal.

Benefits & Sustainability

Installation of precast compound wall creates time and material savings that can potentially substantially reduce construction costs and time.

This is also an environmental benefit, as reducing construction time reduces energy consumption of construction equipment and the impact of workers on the site.  

Since it is made of concrete and steel, it does not support pest infestation. Recycled material can be incorporated into precast wall. Recycled steel can be used as raw material for the reinforcement. The concrete can contain recycled aggregate and be made from locally extracted materials. Some manufacturers have 25% or more recycled content

Manufacturing Process 1.) Moulding Method

2.) Prestressed Method

MouldingIn this type of manufacturing process the concrete mix is poured into the mould ( plastic, pvc, rubber or steel) and then the mould in which concrete is poured is kept aside to harden . According to the necessity the colours , design , size can be varied .Mostly 24 hrs are required to concrete to harden and attain the desired strength . Two types of compound wall can be manufactured 1.) Reinforced Concrete Wall2.) Plain concrete wall

Reinforced pvc mould Steel mould for compound wall vertical pole

Prestressed Method

Pre-stressing is a method in which compression force is applied to the reinforced concrete section.

The effect of pre stressing is to reduce the tensile stress in the section to the point till the tensile stress is below the cracking stress. Thus the concrete does not crack.

It is then possible to treat concrete as a elastic material. There are two basic methods of applying pre-stress to a concrete

member Pre-tensioning – most often used in factory situations Post-tensioning – site use

Pre-tensioningIn Pre-tension, the tendons are tensioned against some abutments before the concrete is place. After the concrete hardened, the tension force is released. The tendon tries to shrink back to the initial length but the concrete resists it through the bond between them, thus, compression force is induced in concrete. Pretension is usually done with precast members

Post tensioning In Post tension, the tendons are tensioned after

the concrete has hardened. Commonly, metal or plastic ducts are placed inside the concrete before casting. After the concrete hardened and had enough strength, the tendon was placed inside the duct, stressed, and anchored against concrete. Grout may be injected into the duct later. This can be done either as precast or cast-in-place.

Design of Reinforced wall panel

Posts shall have typical dimension of 84” height and 50 mm thick

Posts shall be reinforced with 5 Rods of 4mm Prestres wire (typical)

Panels shall have typical dimensions of 120” long by 12" height by 50mm thick

Panels shall be reinforced with 2mm ms weldmesh having 3 horizontal bars and at least 10 to 12 vertical bars.

Cost Comparison

Precast wall costs around rs 120 per sq feet. Brick wall costs around rs 165 per sq feet.

Advantages

The concrete of superior quality is produced as it is possible to have better technical control on the production of concrete in factory.

It is not necessary to provide joints in the precast construction. The labour required in the manufacturing process of the precast units can

easily be trained.

The moulds employed for preparing the precast units are of steel ,pvc or plastic with exact dimension in all directions. These moulds are more durable and they can be used several times.

The precast articles may be given the desired shape and finish with accuracy.

Advantages The precast structures can be dismantled, when required and they can

then be suitably used elsewhere. The transport and storage of various components of concrete for cast in

situ work are eliminated when precast members are adopted. The work can be completed in a short time, when precast units are

adopted. Quality can be controlled and monitored much more easily Weather is eliminated as a factor-you can cast in any weather and get

the same results, which allows you to perfect mixes and methods Recycled aggregates and steel can be used to manufacture precast

concrete products.

Disadvantages

If not properly handled, the precast units may be damaged during transport.

It becomes difficult to produce satisfactory connections between the precast members.

It is necessary to arrange for special equipment for lifting and moving of the precast units.

The economy achieved in precast construction is partially balanced by the amount to be spent in transport and handling of precast members. It becomes therefore necessary to locate the precast factory at such a place that transport and handling charges are brought down to the minimum possible extent.

Product Applications

Compound wall Godown/industrial shed Office building Labour quarters Security Room Road Elevated dividers with Aesthetics look