On the calibration of a shear stress criterion for rock joints to represent the full stress-strain profile

Conventional numerical solutions developed to describe the geomechanical behavior of rock interfaces subjected to differential load emphasize peak and residual shear strengths.The detailed analysis of preand post-peak shear stress-displacement behavior is central to various time-dependent and dynamic rock mechanic problems such as rockbursts and structural instabilities in highly stressed conditions.The complete stress-displacement surface(CSDS)model was developed to describe analytically the pre-and post-peak behavior of rock interfaces under differential loads.Original formulations of the CSDS model required extensive curve-fitting iterations which limited its practical applicability and transparent integration into engineering tools.The present work proposes modifications to the CSDS model aimed at developing a comprehensive and modern calibration protocol to describe the complete shear stressdisplacement behavior of rock interfaces under differential loads.The proposed update to the CSDS model incorporates the concept of mobilized shear strength to enhance the post-peak formulations.Barton’s concepts of joint roughness coefficient(JRC)and joint compressive strength(JCS)are incorporated to facilitate empirical estimations for peak shear stress and normal closure relations.Triaxial/uniaxial compression test and direct shear test results are used to validate the updated model and exemplify the proposed calibration method.The results illustrate that the revised model successfully predicts the post-peak and complete axial stressestrain and shear stressedisplacement curves for rock joints.

An Assessment of Saltwater Intrusion in Coastal Regions of Lagos, Nigeria

This paper explains various factors that contribute to saltwater intrusion, including overexploitation of freshwater resources and climate change as well as the different techniques essential for effective saltwater intrusion management. The impact of saltwater intrusion along coastal regions and its impact on the environment, hydrogeology and groundwater contamination. It suggests potential solutions to mitigate the impact of saltwater intrusion, including effective water management and techniques for managing SWI. The application of A.I (assessment index) serves as a guideline to correctly identify wells with SWI ranging from no intrusion, slight intrusion and strong intrusion. The challenges of saltwater intrusion in Lagos and the salinization of wells were investigated using the hydro-chemical parameters. The study identifies four wells (“AA”, “CMS”, “OBA” and “VIL”) as having high electric conductivities, indicating saline water intrusion, while other wells (“EBM”, “IKJ, and “IKO”) with lower electric conductivities, indicate little or no salt-water intrusion, and “AJ” well shows slight intrusion. The elevation of the wells also played a vital role in the SWI across coastal regions of Lagos. The study recommends continuous monitoring of coastal wells to help sustain and reduce saline intrusion. The findings of the study are important for policymakers, researchers, and practitioners who are interested in addressing the challenges of saltwater intrusion along coastal regions. We assessed the SWI across the eight (8) wells using the Assessment Index to identify wells with SWI. Wells in “CMS” and “VIL” has strong intrusions. A proposed classification system based on specific ion ratios categorizes water quality from good (+) to highly (-) contaminated (refer to Table 4). These findings underscore the need for attention and effective management strategies to address groundwater unsuitability for various purposes.

Framework of Construction Procedure Manuals for PMIS Implementation

Primarily project procedure manuals are intended to enforce company polices or procedures. These manuals are important pieces for successful project management in the construction industry,because construction projects are operated virtually. Even though subcontractors are responsible for field works,a general contractor is still responsible for providing quality project management services for project owners. The more subcontractors involved,the harder it is to monitor and control them, due to the different management processes and procedures they use. More than 36 procedure manuals in the building and industrial construction were reviewed to create process maps of various management services. According to surveys, larger contractors have a broader use of procedure manuals than smaller contractors. The full-scale manuals cover project administration, schedule, cost, contract administration, quality, or safety to home office operations. The small-scale manuals cover from site mobilization, to startup and closeout. Small-scale operation manuals are often used by medium to small contractors. This paper presents suggestions for integrated procedure manuals for construction management firms based on studies of multiple construction procedure manuals. A framework for integrating procedure manuals is presented. The proposed framework can be used to keep uniformity across management procedures and phases. In addition, it can be used to implement a project management system. It can be used to forecast or evaluate management activities through replicability of the management responses.

Analysis of top Chinese contractors' developmental tracks and evaluation of their strategic selection of international construction markets

The past decade has witnessed a rapid development of the international construction market. This research aims to investigate top Chinese contractors' developmental tracks and evaluate their strategic selection of international construction markets over the period from 2001 to 2006,based on the modified Boston Consulting Group Matrix (BCG). Results from 2001 to 2005 indicate that Asia and Africa,which were "question marks" markets for top Chinese contractors (abbreviated as TCCs),have the most potential to become "stars" markets; other question marks markets such as the Middle East and Europe are found not to be of potential; "dogs" markets such as the U.S.,Canada and Latin America should be relinquished progressively unless there is renewed growth opportunity over the next two years. Compared to developmental tracks of top contractors from some advanced countries,TCCs' investment and development strategy in Africa seems to be sustainable and intensive; TCCs' exit strategy for the Middle East appears determined and swift,while their strategy in Asia seems to be lacking in persistence. Furthermore,the data of 2006 indicates that TCCs improve their performance in Asia and Africa,and Africa has become a "stars" market for TCCs.This research sheds important lights and insights into the prevailing process of internationalization of TCCs and provides a strategic direction for their selection of international construction market. What is more,this research is also valuable to other Chinese contractors who are seeking the opportunity to enter the international construction markets.

Feasibility Study of Construction Project in Compliance with Bank Investment Supervision Requirements

On the basis of the 12-year author’s practice of bank investment supervision developed methodology significant construction projects risks have been identified and measured: risks of the highest impact values and risks of the biggest likelihood appearance. The research has been recorded in 400-450 reports of 42 investment projects in advanced manufacturing, commercial, residential, hotels and apartment housing sectors. At least one risk of the highest measured level of significance has been highlighted at each phase of investment process: design, construction and maintenance. A reasonable level of risks significance has been determined which stands for not more than 1/3 of possible significance in “risks monitoring” strategy. EPCM (engineering, project and construction management) approach to investment process and solid, consequent, regular construction projects monitoring executed by professional BSI (banking supervision inspector) makes possible to minimise any faults of inappropriate financing of construction projects.

An Investigation of Waste Management Practices in the Zambian Construction Industry

This study investigated the practice and perceptions on waste management and the feasibility of establishing a site waste management plan in the Zambian Construction Industry (ZCI). In this research, Lusaka and the Copperbelt provinces were selected as study areas to represent the construction industry in Zambia. This was because the largest volume of construction work in the country is mainly concentrated in these two provinces. The research targeted contractors from Grades 1 to 3 as categorised and registered by the Zambian National Council for Construction (NCC). Consultancy firms and government institutions were also included in the target population as regulators. Data for this study were obtained through questionnaires, interviews and site surveys. The results from this research indicated that disposal was the most common method of waste management in the Zambian Construction industry as indicated by the highest ranking score with a mean index of 0.923. The research concluded that the construction industry in Zambia has poor practice of waste management through waste disposal which is not environmentally friendly. The results further indicated that it is feasible to adopt a Site Waste Management Plan in the Zambian Construction industry based on the respondents’ willingness mean score of 0.94 from all the categories. Finally, the research confirmed that a Site Waste Management Plan can be an effective tool to address waste management challenges in the Zambian Construction Industry based on the literature review and willingness measured from research respondents.

Roles and Responsibilities of Stakeholders towards Ensuring Health and Safety at Construction Site

Health and Safety issues in the construction industry are of much concern to stakeholders, particularly because of their impact on the industry. This paper explored the roles and responsibilities of stakeholders in ensuring health and safety at the construction site. A well-structured interview guide was adopted for the qualitative study. Content analysis was adopted for the analysis of the results. The study revealed that the twelve roles identified by the stakeholders are only limited to the few laws and regulations they are aware of. Whereas the Contractors identified provision of welfare facilities, provision of health and safety policy, and health and safety plan as their key roles, the Consultants’ role was mainly limited to provision of competent site agent and provision of site layout. Abiding by the contractors’ instruction was identified by the Construction Workers as their key responsibilities. The local government officials also identified enforcement of CHS laws and regulations and reporting of incidents to the appropriate authorities, whereas the traditional authorities identified the enforcement of CHS laws and regulations including bye laws and enforcement of customs as their key roles. The findings further show that the stakeholders failed to appreciate some key roles and responsibilities enshrined in CHS laws and regulations in Ghana. The findings contribute to knowledge on stakeholders’ responsibilities in ensuring CHS, and provide valuable reference and insight to practitioners on the roles and responsibilities of the various stakeholders. It is recommended to train and educate stakeholders on all the relevant laws and regulations on CHS in order to improve health and safety at the construction site. The government should also set up a body such as Construction Authority to educate, coordinate, monitor and audit the activities of stakeholders to improve CHS at construction sites.

An Assessment of Occupational Health and Safety Regulations in Ghana: A Study of the Construction Industry

Occupational health and safety continues to be a major component of the built environment. The study investigates the effectiveness of occupational health and safety laws and regulations in the construction industry in Ghana and identifies the influencing factors. Face-to-face interviews were conducted among 49 stakeholders from four relevant groups—regulatory institutions, consultants, contractors, artisans and labourers. The findings of the study suggest that the existing occupational health and safety legal and regulatory framework is barely effective. Stakeholders were aware of the existence of some laws and regulations but mostly could not identify the specific laws and their relevant contents. Consequently, compliance is found to be irregular. The key recurring factors affecting effectiveness of occupational health and safety laws and regulations include: negligence and lack of priority for occupational health and safety, lack of training, lack of funds for occupational health and safety, lack of capacity of regulatory and supervisory institutions, and lack of occupational health and safety education within construction firms. The findings of the study are foundational in strategic interventions aimed at improving compliance with occupational health and safety laws and regulations in the construction industry of Ghana.

Critical Barriers to Traditional Project Progress Measurement: Perspectives of Ghanaian Construction Professionals

Accurate project progress measurement is critical for effective project management. Besides guarantying smooth work progress, it affords project managers the chance to identify early warning signs for peremptory remedial actions to keep the project on schedule and to budget. However, pertinent barriers can suppress the realization of the benefits of an accurate assessment of construction progress. This study aims to identify, examine and prioritize the critical barriers militating against accurate project progress measurement in the Ghanaian construction industry. Sixteen barriers identified from the literature were administered in a questionnaire survey to professionals with tier one construction firms and consultants. Sixty experienced construction professionals practising with tier-one construction firms and consultancy services took part in the survey. The relative importance index technique was used to rank the factors and correlation in responses of the two parties tested by the Mann-Whitney U statistics. The most critical barriers perceived by the professionals were 1) Reliance on Supervisor’s Judgement, 2) Generic and Non-Systematic Approach, 3) Variable Quality of Data and 4) Intricate Measurement Reports. Other highly ranked barriers include 5) Lack of Timely Information, 6) Laborious Data Gathering and 7) Quality Integration Constraint. The findings underpin the need to minimize dependence on subjective opinions and mere experiences of supervisors for assessment of project progress in this age of information technology. Incorporation of a level of automation into traditional progress methods will not only reduce human errors introduced into manually collected data but facilitate visualization of progress reports. Contiguous to a clear specification of the method of progress measurement in the contract document, a system that conveniently integrates cost, time and scope of work into progress measurement must be pursued. Addressing these identified critical barriers will consolidate current construction progress management practices.

Major Determinants of Prices Increase of Building Materials on Ghanaian Construction Market

Prices increase of building materials is a common trend in both developed and developing countries. The prices increase of building materials results in high cost of housing.The aim of this study is to identify the major determinants of prices increase of building materials on Ghanaian construction market, and also to assess the relationship between the independent variables of the prices increase. A five-point Likert scale was used for the study;from strongly disagree (1) to strongly agree (5). The variables in the questionnaire were ranked based on the response of the participants of the study using Mean Response Analysis (MRA) statistics. Spearman correlation matrix was used to determine the relationship between the variables of prices increase of building materials. Crude oil prices, energy cost, local taxes and charges, cost of fuel and power supply, high running cost, high prices of raw materials, cost of transportation and the high cost of labour were found to be the major determinants of prices increase of building materials on Ghanaian construction market. The study further found multicollinearity relationship among variables of prices increase of building materials, of which the highest correlation coefficient was found between fast-growing demand due to high global economic growth and over-dependence on imported building materials. The study recommends that further research should be carried out to determine the control measures of increase prices of building materials in Ghana.

Evaluation of Implementation Preparation for CE based on BEACON Model—Taking Construction Enterprises in Yemen as a Case of Illustration

After decades of civil war,Yemen is in a desperate situation,and the construction industry has been suffering from low productivity and poor performance.In order to improve the productivity for the Yemeni construction industry,Construction enterprises must adopt the best and new technologies,new management concepts and philosophies such as Total Quality Management(TQM)and concurrent engineering(CE)owing to achieve improvements in the process of product development.To ensure the successful implementation of CE in the Yemeni construction industry,it is necessary to assess the readiness of those companies to implement CE.In this paper,the BEACON model is used to assess the readiness of the Yemeni companies to implement the concept of CE,that assist in overcoming the construction industry's poor productivity and performance.A study assessing CE implementation readiness will help to promote successful CE implementation in the construction industry and enhance the efficiency of construction companies.The results show that most of the construction companies in the Yemen are not ready to implement CE.The main reason is that the enterprises rely heavily on traditional management methods,and need to improve the organization and management technology.The research results can provide theoretical support for construction companies,especially Yemen companies,to establish basis in implementing an appropriate CE approach for improving performance,and also help international construction companies entering the Yemen construction market to cooperate and implement CE.

Study on the Suitability of Soils in Ilu Aba Bora Zone for Hydraform Block Production for Low Cost Construction

Due to high construction material cost in Ethiopia,it is difficult to afford a shelter for most people.The hydra form block(HFB)has been identified as low-cost building material with its potential and possibility to reverse the housing problem.Laboratory tests were conducted on Mettu,Nopa,Gore,and Hurumu areas soil.Using hydra form machine with average mold size of 29*14*10 cm,hydra form blocks were cast with the three percentages increment of cement.Compressive strength and water absorption tests were conducted at 28 day.The investigation has revealed that all the soil sample except Gore soil have significant characteristics that make it suitable for stabilization with recommended soil properties.From the experimental study,all the blocks except blocks produced with Gore soil have 28th day compressive strength values well above most of the recommended minimum values.Water absorption was less than the maximum limit of 15%.But,for control block and for stabilized with 3%cement,water absorption result is out of the recommended values(0-15)%.The cost comparison of hydra form blocks with hollow concrete block and fired clay brick shows that the hydra form block is cheapest walling material in terms of production cost and a typical hydra form block production center can create jobs for more than 50 people.

The Application of RFID Technologies in Construction

RFID technologies have advanced greatly and deployed successfully in many industry sectors in recent years.Construction industry could benefit from the applications of RFID technologies but as yet has not found sufficient application areas.This project gives a comprehensive awareness of the RFID technologies,which focus on the investigation on the UK construction industry.The current status of RFID in construction and its potentials are specified in the analysis of questionnaires and case studies.Finally,basing on the investigations,some further tasks in developing RFID technologies are carried,including some recommendations,for the construction industry.

Optimization of Mortar Compressive Strength Prepared with Waste Glass Aggregate and Coir Fiber Addition Using Response Surface Methodology

Waste Glass(WGs)and Coir Fiber(CF)are not widely utilized,even though their silica and cellulose content can be used to create construction materials.This study aimed to optimize mortar compressive strength using Response Surface Methodology(RSM).The Central Composite Design(CCD)was applied to determine the optimization of WGs and CF addition to the mortar compressive strength.Compressive strength and microstructure testing with Scanning Electron Microscope(SEM),Fourier-transform Infrared Spectroscopy(FT-IR),and X-Ray Diffraction(XRD)were conducted to specify the mechanical ability and bonding between the matrix,CF,and WGs.The results showed that the chemical treatment of CF produced 49.15%cellulose,with an average particle size of 1521μm.The regression of a second-order polynomial model yielded an optimum composition consisting of 12.776%WGs and 2.344%CF with a predicted compressive strength of 19.1023 MPa.C-S-H gels were identified in the mortars due to the dissolving of SiO_(2) in WGs and cement.The silica from WGs increased the C-S-H phase.CF plays a role in preventing,bridging,and branching micro-cracks before reaching maximum stress.WGs aggregates and chemically treated CF are suitable to be composited in mortar to increase compressive strength.

Effects of hydrogel-encapsulated bacteria on the healing efficiency and compressive strength of concrete

Microbial-induced calcium carbonate precipitation is a promising technology for self-healing concrete due to its capability to seal microcracks.The main goal of this study was to evaluate the effects of adding hydrogelencapsulated bacteria on the compressive strength and the self-healing efficiency of concrete.To achieve this objective,12 sets of mortar samples were prepared,including three different mineral precursors(magnesium acetate,calcium lactate,and sodium lactate),at two concentrations(67.76 and 75.00 mM/L),and under two different biological conditions(with and without bacteria).In addition,a set of plain mortar samples was prepared to serve as a control.For each sample set,three mortar cubes and three beams were prepared and subjected to compression and flexural strength tests.From the compression tests,it was found that the sample containing calcium lactate along with yeast extract and bacteria displayed the best results.As for the flexural tests,once cracked,the beams were subjected to 28 d of wet/dry cycles(16 h of water immersion and 8 h of drying),where the bottom crack width was monitored(at 0,3,7,14,28 d of wet/dry cycles).Once the sample with the highest healing efficiency was identified(the one containing calcium lactate and hydrogel-encapsulated bacteria),the study was scaled up to concrete specimens.Two sets of concrete cylinders(consisting of three control samples and three samples with bacteria along with calcium lactate)were tested under compression in order to evaluate the effect of the bacteria-precursor combination on the concrete mechanical properties.The samples that yielded the greatest compressive strength were the ones containing calcium lactate and bacteria,displaying an improvement of 17%as compared to the control specimen.Furthermore,a flexural strength recovery analysis was performed on the concrete specimens revealing that the control showed better flexural strength recovery than the bacteriacontaining variant(41.5%vs.26.1%)after 28 d of wet/dry cycles.A healing efficiency analysis was also performed on the cracked samples,revealing that the control displayed the best results.These results are due to the fact that the control specimen showed a narrower crack width in comparison to the bacteria-containing samples.

Understanding the Perceptions and Practices of Homeowners in the Event of Hurricane: A Case Study of University Employees in Louisiana

The purpose of this qualitative study is to explore and gain an understanding of Louisiana homeowners’ perceptions and practices in preparing for hurricanes;contribute to academic research and student learning, while guiding the development of future projects. We focused specifically on how homeowners in Louisiana would protect their important documents and possessions. These documents and possessions include but are not limited to photographs, social security cards, birth certificates, and insurance paperwork. We collected the data throughout the fall semester of 2022 at Louisiana State University (LSU) by conducting a focus group and in-depth interviews. We collected a variety of answers, but most participants expressed a strong need to have their important documents and possessions protected and gave different strategies for how this was carried out, such as digitizing or protective storage. Participants also expressed a strong need for more information to be delivered to residents to talk more about ways they can protect their own documents and possessions. Emphases were also made on the need for: leaders of large institutions to be especially concerned with preparedness for vulnerable populations;outreach programs to be put in place to spread awareness of the importance of protecting important documents and possessions during a disaster;news outlets to switch their focus from normal survival tips to discussions on the importance of protecting documents and possessions;government and non-profit agencies to work together to share tips and information through social media and other forms of handouts.