University of Architecture, Civil Engineering and Geodesy

About: University of Architecture, Civil Engineering and Geodesy is a education organization based out in Sofia, Bulgaria. It is known for research contribution in the topics: Finite element method & Beam (structure). The organization has 3808 authors who have published 3822 publications receiving 30736 citations. The organization is also known as: Sofia Polytechnic.

Analysis of Rheological Equations Involving More Than One Fractional Parameters by the Use of the Simplest Mechanical Systems Based on These Equations

Abstract: The behaviour of rheological models containing more than onefractional derivative or fractional operator of fractional orders areinvestigated. All rheological models discussed can be separated intothree groups depending on magnitudes of the valueα*/β* (whereα* and β* are the orders ofsenior fractional derivatives of stress and strain, respectively): themodels are thermodynamically admissible only whenα*/β* = 1 (the first group),thermodynamically compatible only forα*/β* ≤ 1 (the secondgroup) and, finally, thermodynamically well-conditioned both atα*/β* ≤ 1 andα*/β* > 1 (the third group).

Performance evaluation of recycled aggregate concrete-filled steel tubes under different loading conditions: Database analysis and modelling

Abstract: This paper presents a set of data mining analyses on the structural performance of recycled aggregate concrete-filled steel tubes (RACFSTs) conducted using grey relational evaluation and Back-Propagation (BP) neural networks. A comprehensive experimental database containing the results of 20 flexural, 105 compressive and 85 lateral cyclic loading tests of RACFSTs manufactured using conventional recycled aggregates (RAs) (i.e., sieve grading varying from 5 mm to 31.5 mm) and demolished concrete lumps (i.e., sieve grading varying from 50 mm to 300 mm) were compiled through a critical literature review. The influential experimental variables identified through the review of the literature, namely the geometric ratios (i.e., steel tube diameter-to-wall thickness ratio and length-to-diameter ratio), steel tube strength grade, effective water-to-cement ratio, RA content and axial load ratio were selected as the input parameters to evaluate their influence on the structural performance (i.e., load carrying capacity, stiffness, peak strain, ductility and energy dissipation) of RACFST beams and columns. The results of the grey sensitivity analysis indicate that the effective water-to-cement ratio, steel tube strength grade, and steel tube diameter-to-wall thickness ratio and length-to-diameter ratio are in general the most influential set of parameters on the structural performance of RACFSTs, respectively; whereas, the overall performance of RACFSTs is less sensitivity to the RA content when compared with other parameters. It can also be seen from the results that the RA content influence on the seismic performance of RACFSTs is larger when conventional RAs are used in concrete mixes instead of demolished concrete lumps. To extend the parametric range of the experimental database, BP neural networks were employed to estimate the load carrying capacity of RACFSTs, and the results demonstrate that this machine learning algorithm can simulate the effect of RA content on the load carrying capacity of RACFSTs. Based on the extended database, two simple expressions were proposed to model the RA content influence on the axial and lateral load carrying capacities of RACFST columns.

Impacts of teaching approaches on learning approaches of construction engineering students: A comparative study between Hong Kong and Mainland China

Abstract: Teaching and learning contexts influence the learning process and determine the learning outcome or product. Teaching approaches may vary across different engineering and science courses and students. This study was aimed at understanding the differences in teaching approaches between two regions (Hong Kong and mainland China) and their relevant impacts on the learning process in construction engineering education. An exploratory survey was conducted on construction engineering students in China to investigate relationships between teaching approaches, learning approaches, and teaching satisfaction. Results indicate that the “transferring” and “shaping” teaching approaches are commonly used in the first and second class universities in the mainland, while the “transferring” and “traveling” approaches are commonly applied in Hong Kong. Teacher-centered teaching is correlated to a “surface” learning approach among students at Hong Kong universities but it is correlated to a “deep” learning approach for students in the mainland. Students at universities in mainland China are satisfied with all four teaching approaches, “transferring,” “shaping,” “traveling,” and “growing;” while students in Hong Kong are only significantly satisfied with the “growing” teaching approach.