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The increasing complexity of construction, along with its rapid development, as well as ambiguities and gaps in the legal terms governing constructions, lack of trust in the parties regarding obligations and regulations are the main reasons of disagreements in domestic projects. These disagreements are inevitable even in contracts which are set correctly. Disagreements are costly, time-consuming and inconvenient. They also affect the price and quality of contracts. In most projects using different delivery systems, entities particularly contractors may make claims. Moreover, claims and disagreements are inevitable in Design-Bid projects, particularly in Design-Bid-Build (D-B-B) contracts, which are not commonly used in Iran. The focus of this study is the reasons for claims made in projects delivered by Design-Bid-Build (D-B-B) contracts. This study also observes claims related to consulting engineer of the owner. Accordingly, different criteria and sub-criteria are determined to prioritize by decision-making models.

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The purpose of this research to present for the first time a practical plan to cost optimize the composite metal floor deck, so that the designer, by having the dimensions of the main beam framing, will be able to come to the most design including: the section of composite steel beam, the beam span, the thickness of metal deck sheets and the thickness of the concrete slab. The main method of optimization by using metaheuristic algorithm is harmony search which its objective function is equal with these costs: steel beam, metal deck and concrete slab in one square meter of the floor. The standards of this design is according to SDI code and the Iranian National Building Code, Part 10: Design and Construction of steel buildings -allowable stress method. In this design all the metal beam profiles are the common and practical sections in building industry. Also the chosen metal deck, by the brand name Sundeck 75, is the most economical metal deck produced in the country Iran which is invented by the writer 1 and has been confirmed by Road, housing and Development Research center. In the end to ensure all the results of the harmony search optimization, several questions has been optimized, so the comparison of its results with the harmony algorithm results indicates that the high convergence in this algorithm.

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Intelligent building (IB) technologies have widespread applications in the building design and development. In this regard, it is necessary to develop intelligent building assessment models in order to satisfy the clients, professionals, and occupants' growing demands. To this end, this paper proposes an integrated analytic hierarchy process (AHP) and preference degree approach (PDA) under the fuzzy environment for the purpose of intelligent building assessment. Fuzzy AHP is employed to determine the local weights of performance criteria and the final weights of the intelligent building alternatives. Since, the final weights of intelligent buildings (IBs) are in the form of fuzzy numbers, fuzzy PDA is utilized to prioritize the intelligent buildings. Finally, fuzzy AHP-fuzzy PDA is proposed to assess the performance of five intelligent building alternatives in Isfahan, Iran.

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The increase in the number of construction projects and the involvement of a large amount of resources show that one of the most important actions of any construction project is to select the right contractor for the project. Delays in most construction projects and increased costs compared to initial estimates are often due to inadequacies by contractors, indicating that the contractor has not been properly selected. The complexities of the construction industry and the existing uncertainties have led experts to point out that choosing a contractor is a sensitive and difficult task. The purpose of this paper is to design a fuzzy inference system (FIS) to select the best contractor in conditions of uncertainty. The fuzzy inference system is a powerful tool for handling the uncertainties and subjectivities arising in the evaluation process of contractors. The proposed FIS has a two-step computational process in which 28 criteria are determined to evaluate the contractors. The proposed FIS is applied to evaluate and select the best contractor among 5 contractors considered by the general department of roads and urban development in Shahrekord. The studied criteria for evaluating contractors are categorized in six groups, including good history and credibility, equipment, management and specialized staff, economic-financial, skills-ability, and technical criteria. The results show that technical criteria are determined as the most important criteria for evaluating contractors. Furthermore, the results of applying the proposed FIS reveal that contractor C is the best contractor with the final score of 31.40.