Columns at the ground floor and parking garages that could be hit by a car pose a significant risk to the structural stability of the building superstructures. Generally, these columns are not built to sustain the lateral impact force generated by car–column collision. In this study, the performance of axially loaded retrofitted reinforced concrete (RC) columns against car impact is evaluated using finite element (FE) simulation. The FE model of the RC column with axial load was validated with experimental results. For the car-crushing simulations, two SUV car models with a mass of about 2250 kg, which had been experimentally validated, were used to simulate the car–column collision. The results of the FE analysis revealed that once the impact speed exceeds 30 km/h, the horizontal impact force has a significant effect on the column joint at the foundation. The impact force increases linearly as the impact velocity of the car increases up to 20 km/h. When car impact velocities are more than 20 km/h, the generated impact force increases in power to the car-crashing velocity. Both types of cars have almost the same effect on the generation of impact force and the lateral displacement of the column. It is found that the generated impact forces are higher than the recommended design values of Eurocode 1. To protect the column from car impact damage, two types of column-strengthening systems were investigated. One form of strengthening system involves retrofitting the lower half of the column with an aramid fiber-reinforced polymer (AFRP) warp, while the other involves putting a reinforced concrete jacket of up to 1.3 m in the height of the column. Based on the comparative study, design recommendations are suggested to protect the RC column from accidental car-crashing damage.

Fatigue life has to be considered in the design of many concrete structures at various stress levels and stress ratios. Many flexural fatigue test results of plain normal-weight concrete are available in the literature and almost every set of test results provides different fatigue equations. It is necessary, though, to have a common fatigue equation to predict the design fatigue life of concrete structures under flexural load with reasonable accuracy. Therefore, a database of flexural fatigue test results was created for concrete with strengths ranging from 25 to 65 MPa; this database was used to derive new fatigue equations (Wöhler fatigue equation and S-N power relationship) for predicting the flexural fatigue life of normal-weight concrete. The concept of equivalent fatigue life was introduced to obtain a fatigue equation using the same stress ratio. A probabilistic analysis was also carried out to develop flexural fatigue equations that incorporate failure probabilities.

The majority of historical buildings and structures in Oman were built using unreinforced stone masonry. These structures have deteriorated due to ageing of materials, environmental degradation, and lack of maintenance. This research investigates the physical, chemical, and mechanical properties of local building materials and the results of an experimental study on the out-of-plane bending effectiveness of an innovative strengthening method applied to existing masonry walls. The technique consists of the application of a basalt textile-reinforced sarooj mortar (TRM) on one face of the walls. Bending tests of masonry wall samples (1000 mm width, 2000 mm height, and 350 mm depth) were carried out on one unreinforced specimen and three different cases of reinforced specimens. The performance of unreinforced and reinforced specimens was analyzed and compared. The strengthened specimens were able to resist moments of out-of-plane bending 2.5 to 3 times greater than those of unreinforced specimen (160–233% increase). Moreover, the strengthened walls were able to sustain higher deformations (deflections) than the unreinforced specimen ranging from 20 to 130%. The results showed that using TRM was effective for the out-of-plane strengthening of stone masonry using a local material (sarooj) that is compatible with existing stone masonry building materials.