Differing Site Conditions Research Articles

Data-Driven Analysis of Construction Bidding Stage–Related Causes of Disputes

Construction bidding is a complex process that involves several potential risks and uncertainties for all the stakeholders involved. Such complexities, risks, and uncertainties, if uncontrolled, can lead to the rise of claims, conflicts, and disputes during the course of a project. Even though a substantial amount of knowledge has been acquired about construction disputes and their causation, there is a lack of research that examines the causes of disputes associated with the bidding phase of projects. This study addresses this knowledge gap within the context of infrastructure projects. In investigating and analyzing the causation of disputes related to the bidding stage, the authors implemented a multistep research methodology that incorporated data collection, network analysis (NA), spectral clustering, and association rule analysis (ARA). Based on a manual content analysis of 94 legal cases, the authors identified a comprehensive list of 27 causes of disputes associated with the bidding stage of infrastructure projects. The NA results indicated that the major common causes leading to disputes in infrastructure projects comprise inaccurate cost estimates, inappropriate tender documents, nonproper or untimely notification of errors in a submitted bid, nonproper or untimely notification of errors in tender documents, and noncompliance with Request for Proposals’ (RFP) requirements. Upon categorizing and clustering the causes of disputes, the ARA results revealed that the most critical associations are related to differing site conditions, errors in submitted bids, unbalanced bidding, errors in cost estimates, and errors in tender documents. This study promotes an in-depth understanding of the causes of disputes associated with the bidding phase within the context of infrastructure projects, which should better enable the establishment of proactive plans and practices to control these causes as well as mitigate the occurrence of their associated disputes during project execution.

Mitigating Claims and Disputes for Public–Private–Partnership Transportation Projects in the United States

As the construction industry continues to lead the economic growth of many countries, alternative contracting methods have been increasing as a valuable tool to implement on projects. The public–private–partnership (P3) delivery method is becoming an increasingly popular delivery method for megaprojects due to its many advantages, such as private entity financing and the transfer of design, construction operations, and maintenance risks to a concessionaire. As more P3 transportation projects are being executed in the United States, researchers are considering how effectively contracts have been negotiated and drafted between owners and contractors to account for project risks and, consequently, reduce claims and disputes. The objective of this study was to (1) investigate how P3 transportation projects’ contracts are drafted to allocate risks, (2) identify the leading causes of claims and disputes on such projects, and (3) provide recommendations on how risks can be managed and allocated during the contract negotiation phase to reduce claims and disputes. To achieve these objectives, 10 case studies were conducted on 10 P3 transportation projects nationwide with a total cost of $11 billion. The case studies included both content analysis of bid and contract documents and follow-up interviews with project team members to identify risks that caused claims on the projects. The results showed that right of way (ROW) availability, utility relocations, staffing, governmental approvals, and differing site conditions were the leading causes of claims and disputes on the P3 transportation projects included in this case analysis. The results and recommendations can be used to mitigate the negative impact of such risks on future P3 transportation projects.

Species diversity of forest floor biota in non‐native Douglas‐fir stands is similar to that of native stands

AbstractCultivation of non‐native tree species is a promising option to adapt managed forests to climate change. However, consequences of non‐native tree species on flora, fauna, and microorganisms that occur in forest ecosystems (forest associates) need to be considered when managing forests. We lack a solid understanding of how cultivating non‐native tree species in pure stands and in mixture with native tree species impacts abundance and species diversity of forest associates. We compared abundance, alpha‐, beta‐ and gamma‐diversity of eight forest‐floor‐associated taxa that are relevant for ecosystem functioning (including fungi, plants, arthropods, and small mammals) between different forest ecosystems. We addressed pure stands of non‐native coniferous Douglas‐fir (Pseudotsuga menziesii) and two native species, broad‐leaved European beech (Fagus sylvatica) and coniferous Norway spruce (Picea abies), as well as mixed stands of European beech with each conifer in two regions with differing site conditions in temperate Northwest Germany. Diversity indices revealed differences among species groups. Gamma‐diversity and alpha‐diversity of forest associates in Douglas‐fir and spruce stands were usually higher than in beech stands. Estimates of species diversity of mixed stands are intermediate between estimates for the respective pure stands. Differences in the diversity between the two study regions were highly taxon specific with no clear support for a general trend toward a higher or lower species diversity of forest associates depending on site quality. Abundance values show a pattern similar to our diversity estimates, but with a higher statistical uncertainty. Non‐native Douglas‐fir stands provided habitats to support associated species communities of equally high or higher diversity than stands of native beech or spruce. Mixed stands of non‐native and native tree species may be a management option to achieve different goals, that is, to provide habitats for species that are strictly associated with beech and to increase resilience to climate change. However, the overall diversity of forest‐floor‐associated biota is not improved by cultivating Douglas‐fir or spruce in mixture with beech.

Causes of Variation Orders in Road Construction Projects in Tanzania

Background: Variation order has long been an essential component of road construction projects worldwide, being predominantly observed in Tanzania, where road projects are particularly vulnerable. Objective: This study aimed to determine the sources of variation orders in Tanzanian road construction projects and provide a feasible remedy, such as reduction or eradication. Methods: A desk study and questionnaire were utilized as the research approach and analyzed using the relative importance index (RII) method. Results and Discussion: The results reveal that the most significant circumstances causing variation orders are financial problems, weather conditions, differing site conditions, changes in design, poor scheduling, lack of coordination, delay in approval, unavailability of equipment, and lack of communication. Conclusion: Recommended strategies to minimize variation orders were that all involved parties should plan before the commencement of on-site work and perform detailed site investigations. Consultants should ensure that the design and specifications are within the approved budget. All participants were required to spend adequate time in the pretender planning phase. Finally, accurate information and research should be obtained regarding procurement procedures, materials, and plants.

Differing Site Conditions: Clarifying Misunderstandings to Reduce Costly Litigation

Differing Site Conditions: Clarifying Misunderstandings to Reduce Costly Litigation

Causes and Effects of Design Change of Construction Projects

Purpose: Design is the mother of all construction as it is not only technical but also strategic process for competitiveness. In last decade, enormous bridge projects have been designed in Nepal but not all of them have been implemented. The causes of bridge design changes, and their effects on projects in terms of cost and time schedule is found to be complex and are influenced by numerous interrelated factors. This research focuses on the causes, effects and impacts of design change/reviews in bridge projects designed and constructed under Bridge Branch, Department of Roads (DoR). Design/Methodology/Approach: Five case studies were taken along with schedule questionnaire to contrast the causes, effects and impacts identified from questionnaire survey. The data obtained from the questionnaire were analyzed using the Relative Importance Index (RII) for finding the importance of each causes, effects, and impacts. Findings/Result: The design change was found to be done mostly in the foundation of the bridges. Sometime the redesign was done for change in scope and location of the bridge due mostly due to social and political interference and interest rather than value engineering. The Consultant was the main origin agent for design changes of bridge projects as they were the most responsible for the detail survey, soil investigation and design and estimate of the bridge whereas the client found to be second origin agent for design change due to lack of required data, change of plans or scope. The major causes for the bridge design change were Non-complaint design with site requirement, Errors in design, Differing site conditions, unforeseen problems and Inadequate working details. The top three common effects of design changes are time overrun, cost overrun and requirement of additional specialist/equipment/personnel. Originality/Value: It is basic research. This study helps in motivating and creating awareness among the design professionals working in design review which will create the influence to overcome issue of design change strategically. Paper Type: Ex-Post Facto Research

Site conditions more than species identity drive fine root biomass, morphology and spatial distribution in temperate pure and mixed forests

AimThe establishment of broadleaved - conifer mixtures has had positive effects on productivity. However, it is still not clear the degree to which belowground space occupation contributes to these effects and how root traits of the respective species differ between mixed and pure stands. Thus, the aim of this study was to examine how enrichment of beech forests with conifer species impacts fine root biomass and other root traits across variable site conditions. MethodsWe studied 20 mature pure and mixed stands of European beech (Fagus sylvatica), Norway spruce (Picea abies), and Douglas-fir (Pseudotsuga menziesii), and determined differences in biomass, spatial distribution, and morphology of fine roots (≤2 mm, to 60 cm soil depth) among beech – conifer mixtures and pure stands of the respective species in two regions with differing site conditions in Northern Germany. ResultsSite conditions had strong effects on fine root biomass (FRB) and fine root area index (RAI). Both FRB and RAI were significantly higher across all stand types on the sites with lower belowground resource availability. On the less favorable sites, FRB significantly increased with increasing beech proportion. In contrast to specific root area (SRA) and RAI, specific root length (SRL) was not affected by site conditions but differed significantly among species. No overyielding was observed when FRB was plotted against basal area and/or area potentially available (APA), which reflects the aboveground horizontal space configuration. Spatial fine root biomass patterns of all species in both monospecific and mixed stands changed along the vertical soil profile at both sites. FRB decreased with increasing soil depth, with the exception of beech in mixed stands. ConclusionOur data suggest that both amount and distribution of tree fine roots in pure and mixed stands are highly variable and depend primarily on-site conditions and secondarily on tree species identity. By disentangling soil and species identity effects, we conclude that beech has a remarkable potential for adjusting fine root biomass to cope with unfavorable conditions as compared to spruce and Douglas-fir.

Variation Orders and Their Effects of Erbil Governorate Projects

Variation order plays an important role in calculating the final cost and time. The paper aims to determine the causes of variation orders in projects performed between 2007-2014 in Erbil governorate projects. Data was collected from contract documents. Performed in the Erbil governorate projects from 2007-2014. The study seeks to identify the most significant causes of delays by assessing the common causes of delays in terms of frequency, severity and 
 important indices of owners, consultants and contractors related to the implementation of public construction projects in Erbil Governorate. The data acquired from the questionnaire given to the engineers involved in executing of these projects and 73 forms were returned. The results showed that the ranking of overall causes of variation order from highest to lowest was "Contractor's financial difficulties", " Change of plans or scope by owner", "The required labor skill are not available", "Differing site conditions", "Owner's financial problems", "Design change originated by owner", "Errors and omissions in design", " The required equipment and tools are not available", Inadequate working drawing details", and " Change in design by the engineer or consultant". The source of "Errors and omissions in design", "Inadequate working drawing details”, and Change in design by the engineer or consultant" is consultant.
 

Similar successional development of functional community structure in glacier forelands despite contrasting bedrocks

AbstractQuestionsPrimary plant succession is expected to be driven by habitat filtering and competitive exclusion. However, such findings typically come from experimental or single‐site case studies. As a result, we lack field studies that investigate the functional community structures across successional series with differing site conditions. Here, we address the following question: how do plant trait patterns and functional diversity change along two chronosequences with distinct bedrocks?MethodsWe established two soil chronosequences with contrasting bedrock types (siliceous vs calcareous) in the Swiss Alps spanning a terrain age gradient of 13,500 years. We analysed plant ecological strategies at 40 plots per glacier foreland relating six functional traits to terrain age using RLQ analysis. We used the variation in plant ecological strategies revealed by RLQ analysis to calculate indices of functional diversity and analysed their temporal development with terrain age.ResultsThe RLQ analysis revealed that canopy height and dispersal type were significantly associated with terrain age. In both glacier forelands, functional richness (FRic) increased with terrain age, suggesting similar development of niche differentiation along the chronosequences, irrespective of bedrock types. In addition, we observed a decrease of functional evenness (FEve) and functional divergence (FDiv) in both sites, indicating an overall trend to habitat filtering.ConclusionsThe results support the idea of a similar development of functional community structure along the two chronosequences, underlining the deterministic model of functional structure during succession. The functional approach of this study improves knowledge of the adaptive strategies of plant communities colonising glacier forefields and highlights the potential of comparing successional series with differing site conditions to gain a deeper understanding of successional drivers and underlying mechanisms.

Anatomy of Construction Claims

Construction is the backbone of society. Construction as commercial activity channelized through contract document. This document is a combination of obligations of the parties to a contract. It is a document which is interpreted in terms of law and trade practice. In execution of the contract, it is so common that parties have different interpretation and expectation of contract. It is this difference which gives rise to claims and cause for defence against the claims. The effect of claim is to create tension in relationship of the parties and ultimately the progress of work suffers. To solve such difficulties the Resolution Mechanism comes into picture , there are two important aspects viz. constitution of dispute resolution tribunal and the related law. The dispute resolution tribunal is used usually Negotiation, Conciliation, Dispute Resolution Board and Arbitration. Failing all this the matter is reported to law. Various types of claims include Delay damages, Differing site condition, Acceleration and Change of scope claims. All these claims have various facets. It is important to know the anatomy of all these claims as to how they arise and what is necessary to resolve it.

Identification of latent legal knowledge in differing site condition (DSC) litigations

Abstract Conflicts in construction projects have always been a major problem. Unless an alternate resolution mechanism is spelled out in the contract, these disputes are typically resolved in court, which might be time consuming and financially substantial. This paper represents a continuation in a research focused on creating robust methodologies for legal decision support within the construction industry. Consequently, this papers tackles the problem of automating the extraction of implicit knowledge about significant legal factors upon which verdicts of Differing Site Condition (DSC) litigations are based. To that end, the research methodology (1) utilized a set of 600 cases from the Federal Court of New York; (2) adopted 15 legal concepts that have been found to be statistically significant for DSC litigations; (3) implemented 4 weighing mechanism for data representation, namely Term Frequency, Logarithmic Term Frequency, Augmented Term Frequency, and Term Frequency Inverse Document Frequency; and (4) employed Machine Learning (ML) classifiers, namely Naive Bayes, Decision Tree, and PART for the development of 12 prediction models. Among the finding of this study (1) ML classifiers present a suitable solution for the analyzed task; and (2) Naive Bayes classifiers achieved the highest prediction accuracy of 88%.

Impact of Differing Site Conditions on Construction Projects

AbstractThe construction industry plays a very important role in the economy of any country. One of the major risks faced by construction projects is connected with the physical obstructions or cha...

Fairness in Risk Transfer for Differing Site Conditions in Road Construction

Fairness in Risk Transfer for Differing Site Conditions in Road Construction

Rank-Order Analysis of Factors Causing Claims on Road Construction Projects in Botswana

Claims are considered to be one of the most serious disruptive forces to successful project delivery in the construction industry. In a small developing economy like Botswana, it is germane to identify the sources and the frequency of occurrence of claims so that the burden of project cost overrun, a hallmark of the country’s construction industry is substantially reduced. Detailed literature review and preliminary field investigations were used to identify causes of claims related to road construction projects. The study identified six major types of claim and twenty seven causes of claims. Using questionnaire as research instrument, respondents (construction industry major stakeholders i.e. clients, consultants and contractors) were asked to rank the frequency of occurrence of the types and causes of claims in road construction projects on a Likert-type scale. Relative importance index (RII) method was used to analyze the data collected from the questionnaire survey. The analysis was carried out for each group of respondents and on the overall results (all the parties combined). A total of 27 useful responses made up of nine clients, ten consultants and eight contractors) were analyzed. Findings indicated that the clients and consultants specified delay claims followed by extra work claims were the most frequent type of claims in the construction of roads in Botswana. Contractors perceived differing site conditions followed by delay claims as the most frequent type of claims. From the overall response, delay claims were ranked first followed by extra work claims. Acceleration claims were ranked least. The top five most frequent causes of claims based on overall ranking were: variation in quantities, design errors, poor site management and supervision by contractor, ineffective planning and scheduling of project by contractor, and low price of contract due to high competition. Construction industry research in Botswana has never looked into the issue of claims and yet it is one of the hidden sources of construction project failure in the country. It is perceived that hedging against the most adverse causes of claims will stem the tide of incessant cost overrun, litigation and project abandonment on road projects in Botswana.

What Does the Case Law Say? Geotechnical Risk on Design-Build Projects

The growth of design-build (DB) contracting, particularly on public-sector civil projects, has generated a great deal of industry discussion over the age-old question of who should bear the risk of unforeseen conditions. Fortunately for the architect/engineer/consttruction (AEC) industry—and unfortunately for the parties that had to bear the cost and risk of litigation—there are a number of recent cases that help answer this question. As will be discussed in this article, some DC cases specifically address the enforceability of the agency's disclaimer of liability for the geotechnical information contained in the project's Request for Proposal (RFP). Others arise in the context of alleged differing site conditions (DSC) claims asserted by the design-builder. Yet others address conflicts encountered during the design development process for foundations and other geotechnical matters.

Answering the $64,000 Question: Geotechnical Risk in Design-Build Projects

Subsurface risk may well be the aspect of most construction projects that has the greatest potential impact on a project's success or failure. Even when a thorough geotechnical investigation is conducted as part of the design process, the owner may still be liable for differing site conditions found after construction has commenced. Thus, if managing geotechnical risk is difficult in projects delivered using the traditional design-bid-build (DBB) method, the stakes go way up when the owner decides to complete a project using design-build (DB) project delivery.

Analysis of Differing Site Condition (DSC) Litigation Reasoning Through Statistical Modeling

ABSTRACTDiffering Site Conditions (DSC) is considered to be one of the most prominent reasons for claims within the construction industry. Thus, the purpose of this article is to facilitate decision making related to DSC claims through analysis of the judicial reasoning in such cases by identifying significant legal concepts and implementing statistical modeling. The implemented methodology utilizes 60 DSC cases from the Federal Court of New York, extracts legal concepts upon which verdicts are based through content analysis, and develops a binary choice probit regression model to identify (1) the effect of each concept, (2) the associations and precedence of concepts to each other, and (3) the probabilistic change due to parametric variation in these concepts. The findings provide better means of assessing the legal ramifications based on the identified factors. Such evaluation allows disputing parties to make more informed decision about their dispute resolution strategies. In addition, the current research provides knowledge to contractors about factors to which emphasis should be given while bidding for new projects and upon which control should be maintained while performing a project. Finally, this research creates a solid foundation for the development of robust construction legal decision support systems for DSC disputes.

Evaluation of risk factors causing cost overrun in road projects in terrorism affected areas Pakistan – a case study

The risks and uncertainties inherent to the construction industry are more than any other industry and this industry exhibits poor management of these risks. Hence, many projects fail to meet time schedules and budget targets. Transport sector is an important part of the construction industry and is vital to its growth. However this sector has been severely affected by delayed completion of the projects with exceeded cost. These issues are more pronounced in terrorism affected areas around the world, predominantly in Pakistan, Afghanistan and Iraq. Evaluation of Risk Factors Causing Cost Overrun in Road Projects in Terrorism Affected Areas: Pakistan - a Case Study. Pakistan being top ranked terrorism affected country among 85 terrorist affected countries around the world in 2012, has been taken as case study. In Pakistan, Federally Administrated Tribal Area (FATA) being the recipient of max casualties in 2012 is the focus of the study. After 9/11, FATA received maximum share of development projects especially road infrastructure however, these projects could not fulfill their desired purpose due to lack of evaluation of risks associated with the dynamics and culture of that area resulting in severe cost overrun of these projects. This study presents the mechanism to identify the key risk factors contributing to the failure of achieving budget targets of road projects in FATA and suggests measures to overcome them. The study is undertaken via a questionnaire based survey comprising of 18 cost overrun risk factors which were ranked using their mean weightage. Analysis of the results show that non-availability of suitable contractors, project location within FATA, idling cost of plant and equipment due to security threats, differing site conditions in a project and inaccurate survey and site investigation due to security threat were major factors responsible for cost overrun. Moreover, responsibility among the stakeholders for these risks was also established. The results of the study warrant adoption of proactive measures for effective management of these risks by owner, consultants and contractors to avoid budget escalation in road construction projects in terrorism affected area around the world.

CAUSES OF VARIATION ORDER IN BUILDING AND CIVIL ENGINEERING PROJECTSIN NIGERIA

Variation does not only affect labour productivity but also leads to the dispute, time and cost overrun. Consequently, it affects projects performance. It is, therefore, imperative for construction professionals to eliminate unnecessary additional cost from a project so as to optimize the client’s benefit against input resources. This paper identifies and examines the most significant causes that contribute to the variation orders. Also, Nigerian construction industry is used as a case study. Variation orders causing factors were assessed. Questionnaires were administered to clients, consultants and contractors to elicit information regarding variation causing factors. These factors were analyzed using frequency aggregation, mean score method and subsequently ranked according to their severity. The result revealed three most significant causes of variation which are: ‘Change of plan’’ with the highest frequency of 58% then followed by ‘‘Conflicting contract documents (50%). The next most frequent causing factors were the “substitution of materials” and “change in design” each with frequency of 43%. The least causing factor of variation was the “error and omission in design” with the frequency of 10%. Also differing site condition, new government regulation, weather condition were identified as other cause of variation with the frequency of 27%, 29% and 10% respectively. It has also shown that most critical source of variation order is the client due to change of plan then followed by consultant due to conflicting contract document.

CAUSES AND EFFECTS OF VARIATIONS ON CONSTRUCTION PROJECTS

Because of their bespoke nature, construction projects are susceptible to variations irrespective of type, size and complexity. The effects of these variations are significant and may include cost and time overrun, productivity, and waste issues at the minimum. Although variations have been widely researched, investigations into the relationship between the significant causes of variations and their effects have not. This study also considers control measures that could minimize variations in residential building projects, where significant variations are happening in the Sri Lankan construction industry. A questionnaire survey was administered to study participants with the objective of identifying significant causes and effects of variations on residential building projects. The participants were professionals across industry groups such as clients, consultants, and contractors who deal with variations on Sri Lankan construction projects. The study found that change in designs or project scope by owners or design consultants were due to owners’ financial problems, errors and omissions in design, conflicts between contract documents, inadequate working drawing details, lack of coordination by consultants, differing site conditions for contractors, unforeseen problems and weather conditions. Cost and time overruns are subsequent effects of those variations. The study suggests that variations could be minimized by adopting control measures that are appropriate for both the design and construction stage.