Review of Vibration Control Strategies of High-Rise Buildings.

Since the early ages of human existence on Earth, humans have fought against natural hazards for survival. Over time, the most dangerous hazards humanity has faced are earthquakes and strong winds. Since then and till nowadays, the challenges are ongoing to construct higher buildings that can withstand the forces of nature. This paper is a detailed review of various vibration control strategies used to enhance the dynamical response of high-rise buildings. Hence, different control strategies studied and used in civil engineering are presented with illustrations of real applications if existing. The main aim of this review paper is to provide a reference-rich document for all the contributors to the vibration control of structures. This paper will clarify the applicability of specific control strategies for high-rise buildings. It is worth noting that not all the studied and investigated methods are applicable to high-rise buildings; a few of them remain limited by many parameters such as cost-effectiveness and engineering-wise installation and maintenance.

Mechanical performance and environmental impact of normal strength concrete incorporating various levels of coconut fiber and recycled aggregates.

This study presents the fresh and mechanical properties of concrete made with recycled aggregates (RAs) and coconut fibers (CFs), with an emphasis on the development of sustainable and ductile cementitious composite through the valorization of coconut and construction wastes. For this purpose, the effect of different percentages of CF, i.e., 0%, 1%, 2%, and 3% by wt. of cement, was examined on the mechanical and physical properties of concrete incorporating RA (0%, 30%, 50%, and 100%). To avoid the negative effect of CF on workability, a plasticizer was used to achieve the target workability. The performance of mixes was evaluated based on the results of workability, density, compressive strength (CS), splitting-tensile strength (STS), flexural strength (FS), and water absorption. The results showed that incorporation of 1-2% CF improved the CS and STS of concrete for each constant level of RA. The addition of 2% CF is recommended for maximum mechanical performance. Concrete incorporating 50% coarse RA with 2% CF showed CS comparable to conventional concrete. Concrete made with 100% coarse RA and 2% CF showed STS and FS comparable to that of conventional concrete. This study recommends the use of 2% CF along with plasticizer to attain the best mechanical performance. Despite comparable STS and FS, 100% RA concrete with 2% CF produced 25% lower CO2 emissions than conventional concrete.

Mechanical and Durability Performance of Coconut Fiber Reinforced Concrete: A State-of-the-Art Review.

The push for sustainability in the construction sector has demanded the use of increasingly renewable resources. These natural fibers are biodegradable and non-toxic, and their mechanical capabilities are superior to those of synthetic fibers in terms of strength and durability. A lot of research recommends coconut fibers as an alternative to synthetic fibers. However, the knowledge is scattered, and no one can easily judge the suitability of coconut fibers in concrete. This paper presents a summary of research progress on coconut fiber (natural fibers) reinforced concrete. The effects of coconut fibers on the properties of concrete are reviewed. Factors affecting the fresh, hardened, and durability properties of concrete reinforced with coconut fiber are discussed. Results indicate that coconut fiber improved the mechanical performance of concrete due to crack prevention, similar to the synthetic fibers but decreased the flowability of concrete. However, coconut fibers improved flexure strength more effectively than compressive strength. Furthermore, improvement in some durability performance was also observed, but less information is available in this regard. Moreover, the optimum dose is an important parameter for high-strength concrete. The majority of researchers indicate that 3.0% coconut fiber is the optimum dose. The overall study demonstrates that coconut fibers have the creditability to be used in concrete instead of synthetic fibers.

Integrated approach to evaluate unstable rocky slopes: case study of Aqabat Al-Sulbat road in Aseer Province, Saudi Arabia.

In this applied research work, the risk of rock instability in the Aqabat Al-Sulbat road section located in the north-west area of Aseer Province in Saudi Arabia was evaluated, and the primary natural trigger factors of rock slope instability on further environmental components (rock slope stability, road network, and urban areas) were estimated using satellite images (Landsat8), digital terrain models, and geoprocessing in geographical information systems software (classification, overlapping algorithms and production thematic mapping in Arctoolbox). Additionally, field geotechnical investigations testing and over-coring drilling sampling allowed the characterization of the section of road in terms of geological structure and environmental components (geology, morphology, road network, lineaments, and hydrology). As a result, rock slope instability vulnerability mapping was simulated using satellite imagery and geographical information systems (GIS) and ranking natural trigger factors using the combined fuzzy Delphi analytical hierarchic process with the technique for order performance by similarity to ideal solution (TOPSIS) as multiple-criteria decision-making (MCDM) techniques. Additionally, many rock layer discontinuity stations were implemented to evaluate rock slope instabilities, and these were visualized using the Dips program and combined with modeling using 3DEC software to predict rock slope failure based on the distinct element method (DEM) at a small scale. Thereafter, safety factors were computed depending on these previous geospatial data. Finally, vulnerability index mapping was combined with rock instability risk mapping for the Aqabat Al-Sulbat road. Within the framework of sustainable development, these results can be used to inform the urban planning of the municipality of Aseer Province.