The principal factors affecting construction project overhead expenses: an exploratory factor analysis approach

Estimation is the first step in the project development process. Information technology provides an efficient platform for estimators to obtain quotations and specifications for their bid estimates. However, in practice, project overhead estimation relies heavily on the professional judgement and intuition of the estimators. This reduces the overall accuracy and reliability of the bid and a better understanding of the factors affecting project overheads is fundamental before any improved estimating methods can be devised. Unfortunately, the published literature on this topic is very limited. Using exploratory factor analysis, we aim to bridge the current knowledge gap by highlighting the principal factors affecting project overheads. Questionnaires detailing 27 variables were sent to quantity surveying managers of large contractors in Hong Kong. Seventy-nine valid responses were analysed by exploratory factor analysis. From the results, eight factors were extracted with their latent properties identified with reference to the expert opinions collected from telephone interviews. The findings clarify some misconceptions about the factors affecting project overheads and provide useful evidence for practitioners and researchers to understand project overheads. Estimators who address the identified factors when assessing future project overhead costs can improve the accuracy of their cost estimates and project budgets.     

An Empirical Testing of the Economic Base Theory

Most central cities must at present bargain with other units of their regions and the nation for the residents and industry they need; and their bargaining power is so weak as to threaten their viability unless aid from state and federal governments is supplied. Both in order to serve the disadvantaged residents they do attract, and to cultivate their attractiveness to other residents and to industry, cities must re-define “urban renewal” as consisting of large investments in the development of human, land, and transportation potentialities. Such investments must, as all investments, come from “surpluses” which are controlled by the states and the nation, not the cities.     

Non-linear analysis of membrane action effect in profiled steel sheeting dry board flooring system

This study highlights the effect of membrane action in improving load carrying capacity of Profiled Steel Sheeting Dry Board (PSSDB) floor system. PSSDB system is a lightweight composite structural system composed of profiled steel sheeting and dry board, attached together by self-drilling and self-tapping screws. Many literatures have reported that restricting conventional slabs, such as reinforced concrete slab, at the supports against translation and/or rotation while it is subjected to vertical loading develops the compressive membrane action in the slab. The development of this phenomenon is considered in the PSSDB system with concrete infill for continuous and practical spans, with and without topping concrete. Previous authors’ experimentally verified non-linear finite element model for the PSSDB floor without topping was extended to parametrically predict the effect of different boundary conditions on the performance of the system for practical applications. It was revealed that preventing the in-plane movement of the slab ends improves the flexural rigidities of the slab up to more than three times when considering central deflection of serviceability limit state. This was observed when the deflection limit load of the fixed both end supports model was compared to the pin-roller support model. Moreover, the topping concrete enhances the applicability of the system in longer span and the developed compressive membrane action dramatically boosts the load carrying capacity of the slab with restricted translation and/or rotation of the slab ends.     

Development of a continuous respirometer

A continuous oxygen uptake meter or continuous respirometer was developed which produced a rapid and reliable response to systemic shocks. The respirometer basically is a 101. Plexiglas laboratory activated sludge unit with a variable volume air tight side car. The feed enters the completely mixed aeration basin and is pumped into the side car. The side car is the site of the oxygen uptake measurements as indicated by a continuously monitoring dissolved oxygen probe. The system was most sensitive to changes in influent concentrations when run at an F/M = 0.1. Response time for a change in DO of 0.1 ppm was less than 4 min. The continuous respirometer was tested employing both synthetic and raw industrial wastes.     

Effects of copper, pH and hardness on the critical swimming performance of rainbow trout (Salmo gairdneri Richardson)

Critical swimming velocities of Salmo gairdneri at 12°C were determined in different combinations of copper; pH and hardness. Measurements were made after exposure for 0.5, 5, 10, and 30 days. When copper was not applied, hardness, pH and exposure time had no appreciable effect on critical performance. Copper had the greatest effect on swimming performance at 5 days of exposure. At pH 7.5–8.0, recovery from the initial depression was complete after 10 days of exposure, but critical swimming performance did not return to control levels in pH 6.0 treatments. For any given hardness, copper had a greater effect on critical speed at low than at high pH. A given copper treatment had a more pronounced effect at low than at high hardness.No distinction could be made among total, soluble, or extractable copper but predicted concentrations of 6 specific cupric ions varied with pH and hardness. Of these copper species, only Cu²⁺ and CuOH⁺ were found to be related significantly to critical performance.Oxygen consumption of trout was determined in different combinations of copper and pH. In the presence of copper the maximum oxygen consumption decreased and the energy expenditure for a given swimming speed increased.The above observations are discussed in relation to reported toxic actions of copper.     

Rapid Bonding of Ti3SiC2 and Ti3AlC2 by Pulsed Electrical Current Heating

Inspired by pressure resistance welding of metallic materials, herein we describe how two MAX phases—Ti₃SiC₂ and Ti₃AlC₂—were successfully joined by a rapid electric current heating method in a pulsed electric current sintering furnace. No welding agent was employed and the total processing time was less than 6 min. When the bulk temperature of the joint couple exceeded 1070°C, good joints, with shear strength above 50 MPa, were achieved in both homo‐ and heterojunction joints.     

Clearing the Air on EPA's New Chief

On November 8, 2016, the citizens of the United States elected not just a new government, but a very different government. With the election of Donald Trump as the 45th president of the United States and the results in the many contested congressional races, the pendulum of politics swung, perhaps harder than it has swung in at least several decades.     

How Businesses Use Planned Early Dispute Resolution

This is the first part of a two‐part article summarizing the results of a study about why and how some businesses use “planned early dispute resolution” systems.     

A New Synthesized of Ferrous Ricinoleate Mixed with Maleic Dextrose Additive to Enhance Photo and Biodegradation Characteristics of LDPE

Low density polyethylene films blended (LDPE) with mixed Ferrous ricinoleate maleic dextrose additive have been exposed to accelerated UV and biotic environments. The films were accelerated UV light for 70 h before being mixed with water and municipal solid compost. The photo degraded and biodegraded LDPE films were examined by infrared spectroscopy and also to study the photodegraded film attacked by mitochondria β oxidation process of microorganism and its morphological study by SEM analysis and degree of crystallinity behaviour by XRD analysis.