Shaking table test and horizontal torsional vibration responseanalysis of column-supported vertical silo group silo structure

The storage conditions of multi-floor grain warehouses change frequently during grain circulation. This paper investigates the effects of various storage conditions on the seismic performance of multi-floor grain warehouses. The numerical results indicate that the higher the storage material distribution position, the greater the damping ratio of the structural model and the more obvious the contribution of storage material movement to the damping of the structure. The intensity of earthquake action and the spatial height of the floor where the storage material is located are negatively correlated with the acceleration response of the structure. Under full-silo conditions, when the peak ground acceleration (PGA) is 0.4 g, the acceleration amplification factor at the top of the structure is 69.7% of the corresponding parameter at 0.1 g. The discontinuity in the storage space of the structure results in a torsional effect on the structure. When PGA = 0.22 g, the peak inter-story displacement angle of the first floor differs by nearly 1.7 times under different operating conditions, and the peak inter-story displacement angle of the second floor during an earthquake with PGA = 0.40 g differs by about 1.5 times under different operating conditions. The lateral pressure of the silo wall at different burial depths under earthquake action shows a highly nonlinear distribution trend, and the overpressure coefficient at the same burial depth of the warehouse wall is proportional to the PGA of the earthquake action. During 0.1 g, 0.22 g, and 0.40 g earthquakes, the maximum overpressure coefficients at the bottom of the warehouse wall on different floors are 1.13, 1.21, and 1.66, respectively.

Seismic performance of column-bearing silo structure with granular materials considering SSI effect

Augmenting the seismic performance of unreinforced masonry loess - Cave with composite materials through shaking table testing

This chapter presents mitigation strategies for avoiding environmental impacts from fires in waste. Types of waste storage and types of waste are presented, focusing on large-scale waste handling and storage. Potential environmental impacts are affected by the type of storage, such as indoor or outdoor, with or without collection of run-off water. It also depends on the specific waste fraction’s ignition frequency and storage volumes. Any major waste fire, regardless of the type of waste burned, could potentially lead to the release of pollutants into the air, water or soil. Case examples from USA, Canada, Norway and Sweden are presented, as well as studies on emissions from waste fires. There is a need for increased focus on environmental surveillance during and post-fire, and for studies on pollutant composition of smoke and water emissions. Finally, different fire mitigation strategies at waste facilities are presented. Measures that are particularly important to put in place in order to limit the risk of large size fires and of fires spreading include routines for limiting the quantities of stored waste as well as for separating the different types of waste, routines for monitoring the condition of the stored waste, order and tidiness, and access to sufficient equipment for initial extinguishing efforts.

The effects of different types of storage on nutritional quality values of barley and maize are examined. For this purpose, 3 different storage types, including horizontal-reinforced concrete storage, vertical-reinforced concrete silo and verticalsteel silo were taken into consideration. Nutritional quality values (dry matter, crude protein, crude fat, crude fiber, crude ash, and metabolizable energy) of samples were analyzed in the laboratory in four replicates. Total of 438 samples were collected from each of the stored product stacks during the storage for 12 months. Total average nutritional value losses have been found for barley were 1.74% in horizontal-reinforced concrete storage, 1.23% in reinforced concrete silo, 2.82% in vertical steel silo. These values have been found accordingly as 6.21%, 3.02%, and 2.04% for maize stacks. As a result of this research, the vertical steel silo was determined to be more appropriate for maize storage while the horizontal-reinforced concrete storage structure and vertical reinforced concrete silo were suitable for barley storage

Tower structure is sensitive to hurricane and earthquake, and it is easy to generate large deflection and dynamic response. The multiple cardan gyroscope has two rotational degrees of freedom, which can generate strong moments to constrain the two horizontal orthogonal deflections if the rotor operates in high speeds, so the structural dynamic responses can be decreased. Hence, the method of dynamic control of the tower structure under wind load and earthquake action is proposed by using the multiple cardan gyroscopes as the dampers. The dynamic mechanism and the fixed axis principle of the multiple cardan gyroscope are introduced, and the dynamic equation of the gyroscope is established. The damping mechanism of the gyroscope is also described. For the tower structure equipped with the multiple cardan gyroscope dampers, the multidimensional control equation considering torsion effect is established, and the equivalent state space equation is presented. Taking a TV Tower with a number of gyroscope dampers as an analysis example, the structural dynamic responses and damping performance under fluctuating wind loads and earthquake action is studied. The results show that the multiple cardan gyroscope dampers with suitable parameters can effectively decrease the structural vibration in horizontal directions and torsional direction.

In order to study the performance change and interactions between the main structure and glass curtain wall under the individual and coupled actions of wind and earthquake loadings, on the basis of a 98 m high frame-core wall structure in highly seismic region, a finite element analysis model was built by adding the glass curtain wall according to the specifications. Three groups of three-dimensional seismic records are selected according to the site conditions, and the wind pressure time-history of different return periods was obtained through a 1∶440 scale wind tunnel model test. Then the effects of individual and coupled actions of wind and earthquake on the behavior of the main structure and glass curtain wall was studied by the nonlinear dynamic analysis. The results show that the influence of the main structure on the glass curtain wall was greater than that of the glass curtain wall on the main structure. Whether under the individual or coupled actions of wind and earthquake, the inter-story deformation of the main structure was larger than the deformation of the glass curtain wall itself. Under the design and super-intensity earthquake loadings, the nonlinear response of the main structure and the failure range of the glass curtain wall increased with the load increase, and the growth of structural deformation was greater than the base shear's growth. Under the action of wind, the glass curtain wall was not damaged, the main structure was in an elastic stage, and the base shear, top displacement and the maximum story drift ratio increased linearly. Compared with the effect of rare earthquake alone, when the rare earthquake was coupled with 1.1 times wind pressure of a 100-year return period, the torsional effect appears in the structure, and the story drift ratio increased from 1.0 to 1.3. The nonlinear response of the main structure and the glass curtain wall is greater than the simple superposition of wind and earthquake alone. The top displacement and the maximum story drift were 121% and 106% of the sum of wind and earthquake alone. Under the rare earthquake, the coupling action of the rare earthquake and wind earthquake, the failure of glass curtain wall is more likely to happen on the side parallel to the main direction of earthquake.

The rock composition of karst area is mainly limestone, which is easy to be eroded and dissolved by water, forming a complex and fragile tectonics. Under the action of earthquake, the instability of stratum is aggravated. The mid story isolation structure is a new type of isolation structure developed from the basic isolation structure, and irregular mid story isolation buildings are highly susceptible to adverse seismic conditions. Previous studies have mostly adopted the assumption of rigid foundations, neglecting the influence of soil on irregular structures. In order to study the seismic response of isolated structures in irregular planes in karst earthquake prone areas considering soil structure interaction, a finite element model of isolated structures in irregular planes considering soil component interaction was established, and the seismic response of the structure under rigid foundation was calculated. Soft and hard soil foundations were studied, and compared with structures without considering SSI effect. Research shows that when considering the SSI effect, the seismic response of the structure increases and the damage to the structure intensifies; When considering SSI, the seismic response of soft soil is greater than that of hard soil, and the softer the soil, the more obvious it becomes; After considering the SSI effect, the torsional effect caused by the irregularity of the plane increases; The design of building structures should fully consider the adverse effects of soil layers on the seismic response of structures under plane interlayer seismic irregularities. In the design of building structures, it is necessary to fully consider the adverse effects of irregular planes on the seismic response of the structure. This consideration is particularly important in the design of soft soil high-rise buildings in karst earthquake areas to prevent unsafe designs and consider the SSI effect in actual seismic resistance.

In this study, the performances of a solar energy assisted desiccant air conditioning system with different types of storage materials are numerically investigated. In this study four types of storage materials (paraffin wax, stearic acid, capric‐palmitic, and CaCl2·6H2O) are used to obtained the better storage materials can be use for a solar energy assisted desiccant air conditioning system. The numerical results show that, at the same operating conditions the average percentage of energy saving potential approximately reached to 75.86%, 78%, 72.4%, and 64.6% for using paraffin wax, stearic acid, capric‐palmitic and CaCl2·6H2O as a thermal storage materials, respectively as compared to the case without storage materials and solar energy. The life cycle savings reached to 1727.5, 1997.6, 1766.1, and 1534.6 $for using paraffin wax, stearic acid, capric‐palmitic and CaCl2·6H2O as a storage materials, respectively at the same energy cost of 0.039 $/kWh. The results shows that the stearic acid represents a better thermal storage materials use in a solar assisted desiccant air conditioning with thermal storage materials. © 2017 American Institute of Chemical Engineers Environ Prog, 37: 1448–1454, 2018

Under earthquake action, concrete silos can undergo damage over a vast area or may even collapse. To aid seismic design, a numerical simulation of the seismic performance of column-supported reinforced concrete silos was performed, and the performance was quantitatively described. The focus of the research was on determining the damage levels of these silos by adopting an incremental dynamic analysis. The focus of the research was on determining the damage levels of these silos by adopting an incremental dynamic analysis. Four limit states were defined for the first time so as to better determine the damage states of column-supported reinforced concrete silos in the event of earthquakes and the vulnerability analysis of the silo structures was carried out. The analysis results show that volume of the stored grain directly determined its damage behavior. The silo with a greater amount of stored grain entered the plastic state earlier, and the damage effect was more evident. Under the most dangerous working conditions, i.e., the full state of the silo, the 50-year collapse exceedance probability of the silo reaching collapse (LS4) was less than 1% of the 50-year failure risk limit defined in the US seismic design code FEMA P750. This demonstrated that a column-supported reinforced concrete silo can maintain its high anti-collapse reserve capacity under the effect of rare earthquakes.

Irregular structures are prone to torsional vibration under earthquake action, which aggravates the damage of structures. With the development of energy dissipation technology, LRB and BRB are applied to an irregular steel frame. By comparing and analyzing the seismic response characteristics and laws of the original structure, BRB structure, LRB structure and LRB + BRB structure, the seismic performance and advantages and disadvantages of each control scheme are obtained, especially the influence on torsion effect, which provides technical reference for the practical application of such projects.

Optimal utilization of interior building spaces for material procurement and storage in congested construction sites

Torsional repair of damaged single-box multi-cell composite box-girder with corrugated steel webs using CFRP. Part Ⅰ: Experimental investigation

This study discusses the seismic behavior of a geometrically asymmetric three-storey reinforced concrete (RC) building, considering torsional effect and material nonlinearity. The building is a test structure that was used for seismic performance evaluation in the SMART 2013 (Seismic design and best-estimate Methods Assessment for Reinforced concrete buildings subjected to Torsion and nonlinear effects) international benchmark. To begin with, nonlinear stress–strain relationships that were set up for concrete and reinforcing steel are validated by finite element local tests with a representative volume element. A modal analysis shows that the first three calculated natural frequencies are close to the ones that are obtained by modal experiments. The finite element modeling is further validated by comparing the calculated displacement and acceleration due to a low-intensity ground motion with the responses from the corresponding shaking table test. Using the validated model, a blind nonlinear seismic analysis is performed for a series of Northridge earthquakes in order to estimate the behavior of the asymmetric RC structure to high-intensity ground motions. The calculated displacement and acceleration, as well as their response spectra at various sampling points, agree well with the results of a three-dimensional benchmark shaking table test. By investigating the seismic torsional behavior of the asymmetric RC structure, it is shown that the seismic response of an asymmetric structure is larger than that of a hypothetical symmetric structure. The result indicates that a larger seismic response should be considered in the seismic design of an asymmetric structure compared to a symmetric structure with similar design conditions.

The Tana-Beles sub-basin, a strategic economic growth corridor in Ethiopia, relies on water storage to provide a suite of key services to agriculture, drinking water supply, energy, and ecosystems. While there are a range of storage options (e.g., from large dams to subsurface aquifers) that can be utilized to provide these services, a systematic stock-take of literature on water storage in the Tana-Beles has not been undertaken. This knowledge gap constrains the identification of the relative contribution of different storage types in the Tana-Beles. Accordingly, in this study, we conducted a systematic review of literature on the surface and sub-surface storages to examine key issues of the different storage types and their linkages in the Tana-Beles sub-basin. Peer-reviewed and grey publications from various databases were considered for the systematic review. The results indicate that literature in the Tana-Beles sub-basin is more focused on natural storage like wetlands and Lake Tana than built storage types like human-made reservoirs. Overall, the analysis revealed three key points. First, storage volume and water quality in those storages are declining. Second, the causal factors for storage loss and water quality deterioration are agricultural expansion, land degradation, sedimentation, and increasing water withdrawals. Third, the storage gap will increase because of climate change, population, and economic growth while current management options are fragmented. Therefore, the need for more integrated nexus approaches is paramount to optimize storage resources in water, food, energy, and ecosystems in light of population-driven growth in demand and the ongoing global climate crisis.