Comparison of cover meter and ground penetrating radar performance in structural health assessment: case studies

An essential step in the condition assessment of reinforced concrete structures and evaluation of the residual capacity is the determination of the arrangement and quantity of reinforcement as well as the geometry of the structural elements. The objective of this paper is to present the fundamentals in the application of two non-destructive methods, cover meter and ground penetrating radar, in the determination of the above structural features. A comparison of the two methods is presented and their capabilities, advantages and disadvantages are shown through nine case studies.

Influence of near-fault characteristics on inelastic response of multi-storey building with intensity measurement analysis

This study is presented to achieve three objectives: (1) to compare between the inelastic responses of buildings under near and far fault excitations, (2) to investigate the effect of the pulse to structural period ratio, and (3) to evaluate a set of intensity measurements (IMs) in terms of near fault (NF) earthquakes. A real reinforced concrete building with 35 storeys is analysed in the scope of the first and second objectives, whereas the third objective involves three general-frame buildings consisting of 6, 13, and 20 storeys. Results show that the NF excitation can drive the building to exceed its life safety performance level. Furthermore, the accuracy of the IM highly depends on the vibration period of the building and the function used to calculate the IM.

Mw 6.4 Petrinja earthquake in Croatia: Main earthquake parameters, impact on buildings and recommendation for their structural strengthening

Strong Mw 6.4 Petrinja earthquake from 29.12.2020. took 7 lives and caused catastrophic damage in the Banovina area. The paper presents and analyses the most important earthquake parameters and highlights their importance in understanding the damage and demolition of buildings, as well as creating an optimal structure for their reconstruction. A contribution is made to the understanding of the complex mechanism of earthquake formation through the analysis of the stress-strain state in a rock mass during tectonic plate conflict. The causes of demolition and damage to buildings are explained by the combination of the properties of their structure, soil and the earthquake itself. Solutions for optimal structure of new buildings, as well as solutions for structural renovation of damaged buildings are proposed and described.

Application of UAVs for assessment of bridge infrastructure

The shortcomings of classical methods for inspection of transport infrastructure objects have led to the development of more efficient, more reliable, faster and cheaper procedures for condition assessment and load-bearing capacity and service life estimation of objects. In this context, different autonomous systems developed in the last decade have the most notable role and their development is continuously speeding up. This paper provides a state of the art review of the unmanned aerial vehicles application for structural inspection with a focus on bridges. The paper comprises the following: a review of the current regulations prescribing the types and frequency of inspections; a review of the current classical inspection methods with their advantages and disadvantages; analysis of advantages and disadvantages in application of unmanned aerial vehicles for bridge inspections and a review of the equipment commonly used in their development.

Numerical analysis of RC columns under cyclic uniaxial and biaxial lateral load

A numerical finite element study is conducted in this paper to examine structural behaviour of high strength RC columns exposed to biaxial and uniaxial lateral displacement histories with constant axial load. The numerical analysis of 24 models was made using ABAQUS / CAE. The comparison between numerical analysis and experimental results shows good agreement through validations. The considered parametric study involves determination of the longitudinal reinforcement ratio, total cross-sectional area of confinement steel (Ash), and uniaxial and biaxial cyclic shear load. Numerical analysis results show that an increase of longitudinal reinforcement for a uniaxial and biaxial lateral historic load will significantly increase maximum and ultimate load of columns, corresponding deflections, number of cycles at maximum and ultimate loads, and initial stiffness Ki, while the effect of transverse reinforcement is less pronounced. The columns load and deformation capacity decreases significantly with application of biaxial cyclic shear load, compared with uniaxial load. Also, this effect reduces with an increase in longitudinal reinforcement ratio (%ρl) and Ash.

Effects of resins on mechanical performance of polymer concrete

Cement manufacturing is currently responsible for one of the highest levels of carbon dioxide (CO2) emissions and energy consumption in construction industry. Thus, the use of sustainable binder materials instead of cement has become a worldwide issue. Previous studies have shown that polymers are a reliable and sustainable alternative to cement in construction, while polymer concretes (PCs) are seen as the biggest alternative to conventional cement concretes in the long term. In this study, the main objective is to investigate the effects of resins, which are used as binder components in polymer concrete, on the mechanical properties of the PCs. To achieve this, ten different orthophthalic unsaturated polyester resins (OUPR) that are commonly used in construction industry are considered, and fresh concrete tests and hardened concrete tests are performed on deck plates prepared with these resins. Based on the analysis results, each resin is given a performance index. The experimental results indicate that the type of resin has a significant impact on mechanical properties of polymer concrete.

A review of factors influencing performance of pervious concrete

Pervious concrete is an environment friendly solution for eliminating imperviousness-related drawbacks of conventional concrete. Pervious concrete mixes are predominantly composed of cement, coarse aggregate, and water. The partial or complete elimination of fine aggregate results in porous structure, which influences performance of pervious concrete. This article is aimed at reviewing major factors involved in the design of pervious concrete mixes, namely the compaction, aggregate to cementitious material ratio (ACR), sand fraction, water to cementitious material ratio (w/cm), size of coarse aggregate, and void ratio or porosity. The effects of various admixtures, replacement materials, and fibres, are also discussed. The results indicate that pervious concrete acts as an effective medium in promoting the sustainability of urban environments due to its multi-aspectual benefits.

Reducing information asymmetry and building trust in projects using blockchain technology

The success of every construction project is highly dependent on effective communication and trust between key project participants. It is assumed that all participants in the project will work smoothly together to complete the project. Nevertheless, according to the principal-agent theory, there is information asymmetry between project participants because they also have their own self-interests. Information asymmetry is the situation in which one of the two parties is better informed than the other. Due to complexity of construction projects and the number of participants involved, implementation of blockchain technology would reduce information asymmetry. This paper provides a framework for implementation of blockchain technology in construction projects so as to reduce information asymmetry and enhance trust between project participants. Blockchain technology ensures that all project participants have access to all the information exchanged between them over the duration of the project, and thus helps in developing a more trustful relationship between them.

Assessment of core strength of concrete by artificial neural networks

The proposed work deals with the use of Ultrasonic pulse velocity technique as an alternative method to identify compressive strength of the core concrete. The use of non-destructive technique without causing damages to the structure is tedious with interpretation of results influenced by various factors. Hence, an empirical relationship is developed using artificial neural network model for creating a regression between pulse velocity and compressive strength of concrete core specimens. Tests were conducted on reinforced concrete cylinders at various orientation angles (0°, 45°, 90°). The tests were conducted based on the design of experiment using the Box-Behnken model. These results were trained using the Levenberg-Marquardt back propagation model with hidden layers. Results indicate that the prediction of core compressive strength for the grade mixes is nearer for the two-level factorial design with R2 = 0.897, and the sum of squared error is found to be 0.9968.

Evaluation of masonry buildings and mosques after Sivrice earthquake

The evaluation of masonry and mosque type structures after the Sivrice Earthquake is presented in this study. Stone masonry buildings exhibited damage such as vertical cracks and splitting at corners, wedge shaped corner failures, diagonal cracking on walls, out-of-plane splitting of walls, and separation of walls from flooring/roofing systems. On the other hand, the separation of flags and caps of minarets was a common example of damage in mosques. Future earthquake damage can be prevented by following design codes and providing adequate supervision for new structures, while strengthening measures are recommended for the existing buildings.