Research On The Optimization Of Design Risk Management Of Design-build Projects Based On Project Output

In Design-Build(DB)delivery method,design-builders assume design-related risk.It is necessary to realize that design is leading work of project implementation.Hence,failure in design risk management will jeopardize the implementation cost,efficiency and quality of follow-up work,which eventually reduce project outputs.However,research on design risk factors and their impact on the outputs of DB projects are limited.This thesis aims to systematically identify design risk factors of DB projects and investigate the impact of these factors on project outputs.Firstly,a total of 23 design risk factors were identified by exhaustive literature review and interviews.Secondly,a questionnaire was designed based on the identified design risk factors,and then a broad questionnaire survey was conducted with construction practitioners who were asked to rate the impact of the 23 design risk factors on DB project outputs after which 150 valid responses were received.At last,descriptive statistics analysis,exploratory and confirmatory factor analysis were performed on the collected data.The results of data analysis showed that top 5 factors that most significantly impacted DB project performance included unknown project conditions,any inaccurate information in the Employer's Requirement,overlong period of design review required by the employer or employer's deferred design review,employer's excessive right to design review or employer's misuse of right to design review,communication gap or misinterpretation on exchange information between employer and designers.These design risk factors were categorized into six groupings after exploratory factor analysis,namely,risk of improper design-team,risk of designer's lack of responsibility,risk of designer's lack of experience,risk of third-party information,risk of improper design solutions,and risk of design change and employer review.And confirmative factor analysis revealed that risk of improper design solutions,affected by risk of designers' lack of responsibility and experience and third-party information,caused poor project performance statistically significantly.Based on the results of data analysis,the study proposed corresponding risk countermeasures,which helped to optimize the level of design risk management of DB projects.Theoretically,the study contributes to the body of knowledge related to DB delivery method and enriches the research on risk analysis and management.Practically,results of the study can enhance the ability of design-builders to manage design risk,and thus to reduce the possibility of project failure.