Labour Productivity Of The Steel Structure Using Work Sampling Method (Study Case Project Construction of Gelanggang Inovasi dan Kreativitas UGM Yogyakarta)

Abstract

The construction industry requires effective labour management to ensure project efficiency and performance, particularly in structural steel construction. This study aims to analysed labour productivity in the installation of the Joglo steel roof structure at Universitas Gadjah Mada using the work sampling method and to compare the observed productivity with the labour productivity standards specified in the Circular Letter of the Director General of Construction Development Number 182/SE/DK/2025 (SE DJB No 182/SE/Dk/2025). The study was conducted over 12 days of observation involving five labours consisting of two welders and three helpers. The data were collected using the Five Minutes Rate method, resulting in a total of 5.760 observation data points obtained from (12 days × 96 samples × 5 labourers). The results show that the productivity control limits were within an average Lower Control Limit (LCL) of 0,58 and an Upper Control Limit (UCL) of 0,97 with an average field productive of 0,78. Based on the work sampling analysis, the calculated normal time was 3,74 minutes/kg and the standard time was 4,30 minutes/kg. The average labour productivity reached 43,63 kg/day for welders and 29,08 kg/day for helpers. Furthermore, the data sufficiency test produced a value of 451,28. Indicating that the number of observations was adequate and statistically representative. When compared with the productivity standards (SE DJB No 182/SE/Dk/2025), the helper productivity rate of 29,08 kg/day slightly exceeds the benchmark value of 26,67 kg/day. In contrast, the field productivity of welders, recorded at 43,63 kg/day, is significantly lower than the standard value of 80 kg/day. These differences indicate that labour productivity in the field may be influenced by several factors, including labour skill levels, work complexity, environmental and weather conditions, material availability, and managerial supervision. The findings of this study provide empirical evidence of actual field productivity and can serve as a reference for evaluating labour efficiency and improving workforce management in steel roof structure construction projects.