Field-Cast Concrete Research Paper

INTRODUCTION

1.1 GENERAL Precast concrete is a construction product, Produced by casting concrete in a reusable mould or “form” then cured into controlled environment, transported to the construction site & lifted into a place.

The production process of precast concrete is performed on ground level which helps with safety throughout a complete project. There is a greater controlled quality of material. Financially the forms used in a precast plant may be reused ten to hundred times before they have to replaced. This makes the cost of form work/unit to be lower than that of cast in situ production.

Many states across the united states requires a precast plant to be certified by the Architectural Precast Association (APA)

The constructions involve assembling together precast parts which are structural wall panels, shear walls, interior and exterior columns, structural floors, corbel, inverted tee beam, stairs and slabs. These parts can be large such as hollow core slab which are lift in place at the sites by lifting anchor systems.

1.2 GENERAL PRINCIPLES OF PRE-CAST STRUCTURES

 Precast concrete is basically a simple-span material. The continuity can be effectively achieved with properly engineered connection details with and without the use of field-cast concrete.

 Sizes and shapes of components should consider pro¬duction and erection techniques.

 Concrete is a massive material. This is an advantage for such matters as stability under wind and seismic loads, thermal changes, vibration, and fire resistance.

 Maximum economy is achieved with maximum rep¬etition. Standard or repetitive sections should be used whenever possible.

 The most efficient and economical use is largely dependent on an effective structural layout and care¬fully conceived connection details.

 The effects of volume changes caused by creep, shrink¬age, and temperature change and the potential restraint of these effects must be considered in every

 Designing a typical commercial building

 Codal provisions considered include Indian a American & European codes of practice

 Gravity and lateral load analysis carried out as per the standards

 Effect of infill is not considered for the analysis

 Soil structure interaction and material non-linearity is taken into account in the analysis.

1.8 METHODOLOGY

In the present study, a typical building is analysed and designed as per available codes of practice as pre-cast and cast-in-situ structure. The structure is analysed for gravity, earthquake and erection loads. Earthquake analysis is carried out by equivalent static analysis and response spectrum method. In case of precast structure, up to foundation level construction is cast-in-situ, Super structure including beams, columns , floors and wall panels are all precast. The connections are specially designed for gravity and lateral loads. All analysis is carried out using the software ETABS. The parameters compared involves, amount of reinforcement, utilisation ratio, time period, base shear and lateral drift .The cost of materials and construction is worked out as per Indian scheduled rates(SR) for pre-cast and cast-in-situ structures and cost comparison is