Sherif work time decreasing by 0.57%. Moreover, the percentage

Sherif Mohamed, Korb Srinavin 7 in 2005 was presented a simulate the impact of thermal environment on labor productivity, and introduced a new regression model reflecting the relationship between the thermal comfort index (PMV) and productivity. he found the air temperature the most influential thermal environment variable on labor productivity. Xiaodong et al.

8 in 2016 was presented the impacts of high-temperature conditions on construction labor productivity. Labor productivity was measured based on time rather than completed work. The data was collected based on continuous and direct observations for two construction projects involving 16 steel rebar workers in different times during a 54-day measuring period in the summer of 2014 in Beijing, China. Three regression models were built to study the impacts of several factors, including, including the (1) high- temperature environments, (2) laborer age, (3) laborer working experience and (4) laborer BMI (body mass index). The model results demonstrated that high-temperature environments decrease labor productivity, with the percentage of direct work time decreasing by 0.57%. Moreover, the percentage of direct work time increased by 0.

33% when the workers’ experience increased by 1 year and decreased by 0.72% when the workers’ age increased by 1 year. Ezeldin et al. 9 in 2006 developed neural networks capable of predicting the productivity rates of forms assembly, steel fixing, and concrete pouring while incorporating both quantitative and qualitative factors. The researcher used literature review to develop an initial survey form that includes the factors that affect the productivity rates of concreting activities. This initial survey form was discussed during interviews with five experienced project managers.

The survey form was revised and finalized based on the input of these experts. The final survey form on the factors that affect productivity of steel fixing works is (1) Structural element, (2) Steel quantity, (3) Crew size, (4) Supervision, (5) Labor skills, (6) Overtime, (7) Task complexity, (8) Material accessibility, (9) Degree of repetition and (10) Temperature conditions.