A Case Study on Production Enhancement of Precast H-Frames Using Conventional Formwork

 

Er. Auric Das Gupta¹, Prof. B.Ravinder²

¹PGP QSCM  XII Batch, NICMAR, Hyderabad

²Assitant Professor, NICMAR, Hyderabad

 

ABSTRACT:

Precasting might not be a new technique in the construction industry but it is gaining its importance with respect to Project schedule and costs.   To create better and improved facilities, government has taken up many projects to complete in shorter duration.  In the trial of completing the projects, engineers advise to opt the precast technology.  Precasting may be defined as a process of casting the concrete elements away from actual construction to the required specification and dimensions and it is economical if the number of elements is in multiple hundreds.  In this case study, precasting of H- frame is considered and it is as per defined scope. During the course of execution it was observed that the process was on time, but due to revised schedules, the productivity was low. But in the course of time the productivity was enhanced from one precast H-Frames per week to three precast H-Frames per day. This was possible only with proper site layout, proper site operations and proper stocking.

 

INTRODUCTION:

Precasting might not be a new technique in the construction industry but it is gaining its importance with respect schedule’s and costs and government has taken up many projects to complete in shorter duration using this technology. Precasting may be defined as process of casting the concrete elements away from actual construction to the required specification and dimensions and it is economical if the number of elements is in multiple hundreds. Precasting will increase the productivity¹.  Productivity is an average measure of the efficiency of production. It can be expressed as the ratio of output to inputs used in the production process, i.e. output per unit of input.

 

Precast H-Frames:

Precast H Frames (Fig.1) are of varied sizes which are much larger units of approximately 80 tonne weight per unit, and hence their production demands precise planning and execution as per the plan. The process of precasting can be classified into four phases and they are a) Scope formulation,  b) Planning c) Execution and d) Delivery.

 

Case Study:

To discuss the productivity, a case study of Pre-cast H-frame/s has been considered. H-Frames are erected in the assembly of Pipe Racks in Oil Refinery. They are composed of two column components which are connected by one beam component to form a Single H-Frame or two for Double H-Frame (Fig.2). One H-frames can be erected on the cast in situ columns or two, one over the other to form the required no of tiers of the pipe racks. The H-frames are connected with each other by Groutech splicing arrangement² which are filled with non-shrink grouting mortars like  Sika214 or Lanko 701. It is evident that there are many components which have to be taken into account for the production of H-Frame, hence an intricate planning and execution is required for every component starting from its scope formulation to its delivery.

 

CONCLUSION:

To achieve the planned productivity, planning and scheduling shall include time allowance, labor risk, skill risk, material risk, execution risk, mobilization risk of  pre-casted elements to work execution site,  machinery risk and pre cast yard layout risk  etc.,

 

REFERENCES:

1.       Bechler, J.G (1984). "The Productivity Management Process". American Productivity Center.

2.       http://www.dextragroup.com/groutec

3.       http://www.bigge.com/crane-charts

 

Received on 12.11.2015            Accepted on 24.12.2015            © EnggResearch.net All Right Reserved Int. J. Tech. 5(2): July-Dec., 2015; Page 169-172 DOI: 10.5958/2231-3915.2015.00015.2