Journal of Rehabilitation in Civil Engineering
Volume:10 Issue: 2, Spring 2022

Tuned liquid column ball dampers (TLCBDs) are a relatively new type of liquid dampers in which the motions of liquid in a U-shaped tube counteracts the forces acting on the structure. Damping in the oscillating liquid is introduced through a steel ball rolling by the liquid passage. The tube and steel ball in a single TLCBD-system may acquire enormously large dimensions. One way to decrease the size, and perhaps the total costs, is to replace a single-TLCBD with a multiple (M)-TLCBDs of smaller dimensions. Current literature lacks to address the governing equations of an M-TLCBD and its application in wind response mitigation of tall buildings. In this paper, the governing equations of motion for an MTLCBD-system has been developed. Next, the dynamic response of a tall building, equipped with various MTLCBDs, to harmonic wind excitations is investigated. The influence of different design parameters such as mass ratio, length ratio, and the number of individual dampers on the response mitigation efficiency of MTLCBDs has been studied. Overall, the performance of a MTLCBD is found to be sensitive to the variations in the design parameters mentioned above.

Failure of appropriate resource structures for petroleum products located close to residential areas has irreparable financial and fatal consequences. Thus, a seismic hazard analysis in estimating strong ground motions seems essential for constructing or improving such structures. For this purpose, firstly, by using the deterministic method and empirical equations of the largest earthquake likely to occur, the result of active faults activity was determined using attenuation equations via an appropriate logic tree, and the maximum horizontal and vertical acceleration component was calculated based on two types of soil. The first type of soil matches types I and II, and the second type matches III and IV, from standard No.2800. Then, to analyze the potential hazard, we define the seismic sources, seismic parameters, rupture parameters, and the attenuation equations with the same logic tree using SeisRisk III software, plus the maximum vertical and horizontal acceleration component, based on the two identical types of soil. Subsequently, the seismic improvement regulation of structures (360 magazine) for the second level hazard was calculated and finally compared with the results of the deterministic analysis. Results indicated that the acceleration component in the deterministic method presents a higher amount than the probable method. As a result, probable methods can be used instead of a deterministic method proving far more economical.

Structural height set-back is a particular type of irregularity that affects the performance of the structure significantly. Therefore, researchers have always been interested in the effects of height irregularities on the seismic performance of such structures. The present study aimed to provide an optimal design based on the seismic performance of three- and nine-story steel moment frames with set-back in height. The study proposes a method that takes the acceptance criteria into account by analysis in two directions for the optimal design of steel moment frames with setbacks. Optimization in the present study aims to reduce the structural weight and obtain uniform inter-story lateral drift distribution through the acceptance criteria for each performance level. The optimization process is performed using meta-heuristic algorithms of Accelerated Water Evaporation Optimization and Accelerated Water Evaporation Optimization. The results show the efficiency of algorithms to finding the optimal solution and the appropriateness of the proposed procedure.

In recent decades, with increasing in traffic load, a great portion of repair and maintenance budget is being spent on improving the pavement failure. Asphalt fatigue, which is due to traffic cyclic loading, is one of the most important failure in asphalt pavements, therefore, increasing fatigue life in pavement can lead to a decrease in repair and maintenance budget. As a result, replacing or adding some additives to improve the fatigue behavior of the asphalt mixture, can help to reduce the fatigue cracks and increase the mixture life. In this research, fatigue behavior of asphalt mixture has been analyzed by using four point bending beam test with constant strain method on control and modified specimens with cement, coal waste and lime as filler. Fatigue behavior has been assessed at 2 strain 400 and 600 with replacing cement, coal waste and lime as the filler in the mixture. Results show that using each of 3 fillers at both strain state, leads to an improvement in fatigue life of asphalt mixture. Analyzing the results show that using above fillers could be used as an approach to improve the pavement’s function. Quantitatively, the three fillers, cement, coal waste and lime improved the fatigue life compared to the witness specimen by 75%, 55% and 8.2% at strain state of 400 and 107%, 72% and 7.1% at strain state of 600, respectively. Using coal waste can reduce the environmental issues due to coal waste deposits in addition to improving the fatigue life of asphalt mixture.

The applications of plate like structures in different fields of engineering are increasing. In this paper, a new damage detection method investigated based on Gaussian process regression model (GPR). GPR is an efficient learning machines which has been used in different fields of engineering. To identify damage, mode shaped and natural frequencies of damaged structures used to train GPR. Finite element modelling of numerical examples and Gaussian process regression (GPR) model are carried out within the MATLAB environment. To show the effectiveness of presented approach, a two-fixed supported plate and a cantilever plate was studied. In other work, a comparative study has been done using a cantilever plates. The natural frequencies were contaminated with noise in above mentioned numerical examples. Results reveal that the proposed method works well using the only first mode data which may be noisy. In other word, GPR can be trained using limited sample numbers for training.

This paper aimed at assessing the in-situ strength of steel fibre reinforced concrete containing recycled coarse aggregate (RCA) using the correlation between ultrasonic and point load tests. The mechanical properties of recycled aggregate concrete can be improved by adding fibres in concrete mixes. On the other hand, the importance of strength estimation of existing concrete at the building site has led to use non-destructive and partially testing methods. So, in this research, the compressive strength of wet and dry cured mixes made with RCA and steel fibre (SF) at 1.5% by volume was evaluated by mean of point load test (PLT) and ultrasonic method. As per the experimental outputs, the standard deviation (SD) values increased up to 20% by increasing the substitution amount of natural aggregate with RCA from 50% to 100%. In addition, the point load index (PLI) of wet cured concrete mixes was obtained averagely about 14.3% more than that of dry cured concrete mixes. Furthermore, the strength estimation of conventional concrete or fibre reinforced recycled aggregate concrete at different ages was carried out using a two-variable equation between ultrasonic pulse velocity (UPV) and PLI values.

The use of concrete as parent material is now an old technique, but it is widely used today due to its unique characteristics. India has witnessed development in the construction field from Harappa civilization to the British era for many years. Even after independence, in 1947, India has advanced in construction techniques in concerning time. However, improper management, design, and ignorance of repairs and rehabilitation of structure cause the collapse of buildings which causes many deaths to occur every year in Mumbai and throughout the country. But the people living in dilapidated buildings risk their lives. Many people are constrained to live in them due to various reasons like skyrocketing rise in real estate prices, fear of losing their houses after vacating for redevelopment projects. Repair and rehabilitation are significant for preserving the structure’s capacity and increasing its performance capacity, which deteriorates due to aging factors, environmental factors. The recent collapse of the building named Tarique Garden in Mahad caused the deaths of 20 people. Considering this as a manufactured disaster, it made a national highlight seeking the attention of mainstream media. A sample space of buildings from buildings in khed city, about 200 km from Mumbai, is taken as a research area as this is a developing city near Mahad city where the incident occurred. This paper aims to determine the various risks involved in dilapidated buildings by studying various health and safety factors that affect the age of the building. This research also focuses on scrutinizing various problems faced by the residing people in dilapidated buildings. The methodology adopted in this research is by doing unstructured interviews with a questionnaire survey of tenants, performing field surveys of various structures in the study area, and segregating the buildings based on the building’s various safety and hygienic conditions. The result shows the DI (Dilapidation index) score, which is done based on the comfort level of tenants. Finally, this research signifies accomplishing various action plans taken by government authorities towards dilapidated buildings and proposing some suggestive measures that would help minimize such accidents.

In this study, the replacement of corroded reinforcement with new reinforcement as a rehabilitation method is considered to reduce the impact of corrosion on the performance of reinforced concrete structural elements. Also, the effect of using high-performance concrete with the method of reducing the water-to-cement ratio, as a method for maintenance of reinforced concrete structures, has been analyzed. So, the influence of the above rehabilitation methods for maintenance of reinforced concrete structures on the corrosion initiation time of reinforcement, crack initiation time and crack width of the concrete cover thickness, the service life of a reinforced concrete structure due to corrosion, and corrosion percentage of reinforcement have been investigated. For this purpose, all equations and connection between them for the corrosion phenomenon modeling (including corrosion initiation phase, corrosion propagation phase and cracking) is integrated, and the corrosion parameters are calculated and compared for the marine environmental conditions. The results indicated that, the end time of service life of a reinforced concrete structure due to corrosion (tf) increases 60.54% by applying the new reinforcement as a rehabilitation method. So, in concrete with a water-to-cement ratio of 0.35, the corrosion percentage of reinforcement in the new-reinforcement scenario has decreased by 15.60% compared to the no-repair scenario over 30 years.

Chloride ingress in concrete leads to deterioration of reinforcement and subsequent distress in concrete. The focus of the present study was to determine the amount of chloride ingress in concrete with and without supplementary cementitious materials (SCM) using Rapid Chloride Penetration Test (RCPT) and Rapid Chloride Migration Test (RCMT). A comparison of chloride ingress was made of Control concrete with six other mixtures having varying percentages of fly ash (20% & 30%), ground granulated blast furnace slag (GGBFS) (30% & 40%), silica fume (5%) as replacement of cement. Compressive strength, RCPT and RCMT tests were evaluated for all the mixtures after 28 and 90 days respectively. A correlation between RCPT and RCMT tests was established. Mixtures containing fly ash as SCM had lesser initial compressive strength compared to mixtures with GGBFS and silica fume. Chloride permeability of concrete mixture with silica fume as SCM has a significant decrease in chloride permeability in both RCPT and RCMT tests at both ages compared to concrete without SCM. Estimation of service life was carried out using Life-365TM software. It was observed that the service life of concrete without SCM was estimated to be 14.8 years while in the concrete with 5% silica fume expected service life was 24.9 years. Thus, the incorporation of supplementary cementitious material in concrete enhances the service life and is a boon to the construction industry.