This paper deals with a comparative study of an optimal design regarding composite steel and concrete floor structures based on the performed multi-parametric mixed-integer non-linear programming (MINLP) approach, and Eurocode specifications. The optimization models COMBOPT (COMposite Beam OPTimization) were developed and cost optimizations of the structure alternatives were performed. A series of MINLP optimizations were executed over a wide range of various design parameters: different material unit prices, hourly labour costs, imposed loads, structure spans, steel and concrete grades, welded and standard steel sections, plastic and elastic cross-sectional resistances, different positions of the neutral axis and different locations of the centre of gravity axis of the transformed (all steel) section. The Modified Outer-Approximation/Equality-Relaxation (OA/ER) algorithm was applied. The minimal self-manufacturing costs of the structure, steel and concrete grades and standard sizes were obtained through each individual MINLP optimization. All the results were analysed and compared. Comparative diagrams and a recommended design for a composite floor system were determined. In addition, this study answered some questions regarding the influence of unit prices on the optimal design, the most suitable position of the neutral axis, the competitive spans of the structures with welded and standard steel sections, the competitiveness of the plastic cross-section resistance when compared to the elastic resistance, the spans and loads where the ultimate and the serviceability limit states are predominant and the adequate location of the centre of gravity axis of the transformed (all steel) section.
COBISS.SI-ID: 19992598
The paper presents an optimal design of timber-concrete composite floors based on multi-parametric mixed-integer non-linear programming (MINLP) optimization. For this purpose, the MINLP optimization model TCCFLOOR was developed. The model comprises an accurate objective function of the structure production costs, subjected to design, resistance and deflection constraints in order to satisfy the requirements of the ultimate and serviceability limit states according to Eurocode specifications. The multi-parametric MINLP optimization was executed for various design parameters like different vertical imposed loads on the structure, different structure spans, different alternatives of discrete cross-sections as well as different timber and concrete strengths. A recommended optimal design for timber-concrete composite floors was obtained and presented at the end of the paper, developed from previous MINLP optimization results. Economically suitable spans for timber-concrete composite structures were also found.
COBISS.SI-ID: 20740374
Significant research effort has been focusing on automated construction progress monitoring using the Scan-vs-BIM method. In recent years, various scanning technologies were applied with different success. The general finding is that a higher quality of the point cloud leads to improved monitoring results. Most published works in the relevant area recognise density and accuracy as the main quality parameters of a point cloud. Data quality has been addressed in various ways, by defining arbitrary levels of quality parameters, by evaluating the quality parameters of a point cloud, and by defining parameters of a scanning plan in order to achieve a desired level of quality. However, the relation between the levels of point cloud quality and the success of Scan-vs-BIM element identification is still an open question. This paper presents results of a research in which we defined a more accurate and applicable metric for evaluation of the quality of a point cloud for construction progress monitoring using a Scan-vs-BIM method. The proposed methodology includes the definition of building element classes and the definition of point cloud quality parameters, which have been selected by observing the most significant criteria that influence the success of building element identification. Using a test BIM, around hundred point clouds have been generated with combinations of influencing parameter values. A statistical method was applied to determine the point cloud quality criteria for assuring correct identification of each class of elements. The quality criteria were then validated using three different scanning methods. Results show that the defined quality criteria can be effectively applied in deciding on the appropriate scanning methodology for successful Scan-vs-BIM identification.
COBISS.SI-ID: 20843542
The primary benefit of fuzzy systems theory is to approximate system behavior where analytic functions or numerical relations do not exist. In this paper, heuristic fuzzy rules were used with the intention of improving the performance of optimization models, introducing experiential rules acquired from experts and utilizing recommendations. The aim of this paper was to define soft constraints using an adaptive network-based fuzzy inference system (ANFIS). This newly-developed soft constraint was applied to discrete optimization for obtaining optimal solutions. Even though the computational model is based on advanced computational technologies including fuzzy logic, neural networks and discrete optimization, it can be used to solve real-world problems of great interest for design engineers. The proposed computational model was used to find the minimum weight solutions for simply-supported laterally-restrained beams.
COBISS.SI-ID: 20691222
The presented study is focused into examination of the building shape influence on the annual energy need for heating and cooling by taking into account climate data for six European cities located in different climatic regions. The research is performed on timber-glass box-house models parametrically varying building aspect ratio (L/W) and number of storeys (single- and two-storey), while the glazing - to - wall area ratio for southern façade is kept constant for all treated models (AGAW=35%). The influence of the mentioned parameters on the annual energy need is thoroughly analysed and leads to completely different conclusions drawn for cold and warm climate conditions. According to the presented results the recommendation for cold climate conditions is to design two-storey houses rather than single-storey ones. Additionally, the increasing aspect ratio shows a positive influence on the energy need reduction. In the case of warm climate conditions the findings are almost opposite to those for cold climates. The total energy need consist predominantly of data for cooling, whereby the energy need increases with the increasing aspect ratio. On behalf of specifics related to warm climate a further study was conducted for Athens with an additional examination of the building components with higher thermal transmittance (U). The results of the research for Athens show that designers are practically free to choose between single-storey or two-storey buildings with no significant impact on the building energy behaviour. The main output of the current study is to offer designers general information on energy-efficient design parameters for single-family timber-glass buildings under influence of different European climatic conditions.
COBISS.SI-ID: 21048086