Section II

Mechanization and Performance Analysis of Vertical Slip Form Wall Construction Technology

Authors:

Abstract

Building construction industries in Sri Lanka are currently facing burning issues due to lack of construction materials, transportation and high labour cost. Masonry wall construction and plastering is one of the most important jobs of small and large building construction. The slip form technology is an alternative wall construction method, introduced to the Sri Lankan construction industry in 1980, instead of burnt clay brick walls or cement sand block walls. The conventional slip form wall construction technology was commenced by the National Engineering Research & Development Centre (NERDC) with a fully manually operated system consisting of steel shutters, yokes, hydraulic jacks, and manually operated compaction hammers. An amount of 10% cement with quarry dust mix volume is sufficient to get required strength (cement quarry dust ratio is 1: 10) and it can be used as a load bearing wall between columns. The system has identified main drawbacks while construction of a wall such as uneven compaction due to manual compaction, high operational and shutter lifting time etc.

 

NERDC has been studying and developing a mechanized slip form wall construction machine in order to promote this technology in the society. The machine consists of a single phase 230 V hydraulic power unit, two slip form shutters, two lifting hydraulic cylinders and a movable vibrator compaction unit. Cement quarry dust mixer compact between columns by vibrating and applying a maximum of 140 kg static load by a hydraulic cylinder. Shutter lifting total vertical force measured is 620 kg with overcoming friction between metal shutter and newly bonded wall. Compaction ratio obtained was 40% to 45% varying with moister content of a mixer. Average wall construction rate is around 75 to 80 min/m. A standard 140 mm diameter cylindrical core was tested with the test results for 150 mm thick and 2900 mm span wall showing an average strength of 4.9 N/mm2 after 28 day completion of wall. The average shutter lifting speed was measured as 24 mm/second. The machine was tested up to 10 feet wall height continuously. The tactile controlled basic hydraulic system was employed to improve better man machine interface with the entire operation. High initial setting time and heavy weight are the main drawbacks identified while operating the system with three operators. It is likely that four operators are required to achieve a better performance from the system.

Keywords:

Slip formVibrationCompactionTactile controller
  • Year: 2019
  • Volume: 52 Issue: 2
  • Page/Article: 45-56
  • DOI: 10.4038/engineer.v52i2.7353
  • Published on 12 Jul 2019
  • Peer Reviewed