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Thermal behaviors significantly affect the contact stiffness and position accuracy of the rolling linear guide, which worsen the performance of the precision machinery. In this paper, based on the modified lumped capacitance method (MLCM) and finite element method (FEM), a thermal model of rolling linear guides has been formulated in terms of the geometric parameters, friction, gyroscopic moment, and loading conditions. Experimental results show that the thermal model can well predict the real-time temperature variation under different working conditions. Further analysis shows that, the applied vertical load, carriage velocity, and toque load significantly influence the temperature variation of linear guides, while the influence of the torque load on temperature variation decreases with increasing vertical load levels. Besides, the reasons of the steady-state temperature variation considering the load distribution model are also discussed.

La primera parte de esta investigación presenta un modelo optimizado para cabezales o zapatas rectangulares apoyadas sobre un grupo de pilotes para obtener la superficie mínima en planta (área óptima) que soporta una carga axial y dos momentos sobre el eje X y Y debido a una columna. La presente investigación muestra el diseño óptimo (costo mínimo)para cabezales. Este modelo considera que los cabezales son perfectamente rígidos y los pilotes están articulados en la unión de los cabezales con los pilotes y, por lo tanto, los pilotes transmiten solamente carga vertical. La metodología normalmente utilizada para obtener el diseño de los cabezales considera que todos los pilotes transmiten la misma carga vertical; esto funciona únicamente cuando la columna transmite carga axial y no momentos. Además, cinco tipos de cabezales apoyadas sobre un grupo formado por dos, tres, cuatro, cinco y seis pilotes se muestran para demostrar la precisión del modelo presentado en este documento

In the rigorous analysis using FEM, the load sharing of the piles between the shaft and base resistance increased with increase in limited number of piles i.e. limited to decrease in pile spacing. The load sharing depends upon their location and spacing. The load carried by the center pile reduces with the increase in the number of piles and piled area. For the edge piles, it increased with the increase in the number of piles, whereas decreased for the corner piles. The total load carrying capacity of the piles increased with the pile sizes and spacing. The piled raft settlement decreases with the increase in the number of piles. By rearranging the same number of piles, more settlement of piled raft is observed for less pile spacing, which concentrated at the center, and the settlement is decreased with increase in pile spacing, which scattered outwards. Increased in number of piles is not always advisable and expensive. Based on limitation in settlement as specified by the code, limited number of piles and pile spacing are recommended. The settlement profile along the centre line of the piled raft decreased with the increase in the number of piles and more flexible at larger pile spacing.

There has been considerable interest in stratospheric airships as a cost-effective alternative to earth orbit satellites for sightseeing, aerial photography, communication and carrying weapons, etc. Many countries have plans to develop the airship owing to its greatly expected usage. The suspended curtain plays a vital role in force transmission in stratospheric airships but lacks attention. In this paper, the relationship between the optimal shape of suspended curtain and load conditions was studied through CAE Abaqus and Isight. Firstly, by using secondary development function of Abaqus, parametric FEA models of suspended curtains and envelopes have been established, several parameters were used to describe the shape of suspended curtains. Secondly, parameters of the suspended curtain shape were optimized under different loading conditions by means of the genetic algorithm. Lastly, through the analysis of the results, some conclusions are summarized: The relationship between n1(n2) and nb was found to be linear when the suspended curtain is subjected to vertical load. The stress transfer law of suspended curtain and inflatable membrane structure under the inclined load were also obtained, which are valuable for the structural engineering design of stratospheric airships..

Two-dimensional foundation models have been established based on the discrete element method (DEM). By loading the top plate, foundation instability processes under four different values of inter-particle friction were able to be simulated. The evolution of the force chains and contact network within the affected range of the bearing plate were studied. The results indicated that during the loading process, the force chain that transmitted the load from the loading plate gradually grew along the trapezoidal belt, and the number of stable force chains gradually increased until the quantity stabilized. For most of the loading process, the evolution trend of the n-cycles indicated that the n-cycles with more edges gradually evolved into n-cycles with fewer edges. From the point at which the reconstruction of the force chains was completed to the point at which foundation failure occurred, the vertical load and coordination number displayed a linear relationship.

Motion resistance of tyres directly contribute to the operational costs of all vehicles. Advances in the design and simulation of large off-road vehicles (construction, mining, agriculture etc.) have increased the need for accurate models of large off-road tyres. Vehicle OEMs use coast down and drawbar pull tests to determine the motion resistance of tyres used. Drum test rigs and motion resistance test trailers can also be used to determine motion resistance. Most research on motion resistance to date have been conducted on passenger car tyres with on-road truck tyres coming into focus. Motion resistance studies on agricultural tyres traversing over deformable terrain have been conducted in the past. However as more off-road vehicle are being used on-road OEMs of off-road vehicle are infesting in motion resistance measurements on non-deformable terrain. This paper compares different methods used to measure the motion resistance of a large lug tyre, as used in agricultural applications, on non-deformable terrain. Some basic considerations that need to be taken into account are the very low longitudinal forces that need to be measured compared to the large vertical load carried by the tyre and tyre operating conditions.

Many column-supported embankment (CSE) design methods include geosynthetic reinforcement for vertical load transfer and/or settlement reduction regardless of project conditions. However, geosynthetic reinforcement may not be necessary for all applications, particularly if a sufficiently thick and strong soil layer overlies the compressible soil. A strong soil layer can transfer embankment loads to the columns without much differential settlement at the base of the embankment, limiting the development of tension in the reinforcement. If weak and compressible soil extends to the ground surface and the area replacement ratio is low, differential settlements may be so large that it may not be practically possible to provide enough reinforcement to avoid excessive strain or rupture. This paper describes parametric studies using the Load Displacement Compatibility method to investigate the influences of embankment height, geosynthetic stiffness, column diameter, and thickness of an upper sand layer on geosynthetic strain, differential settlement at the base of the embankment, and load distribution among the CSE components. Results of the parametric study show that site conditions, CSE system geometry, and performance requirements limit the range of circumstances for which geosynthetic reinforcement for settlement reduction is needed, effective, and practically possible.

Introduction: A well-constructed two-implant-assisted mandibular overdenture can be a successful treatment option for completely edentulous patients as it helps improving the oral function and patient satisfaction through elimination of the fear of dislodgment during speech or mastication. Various attachment systems can be used for retaining mandibular overdentures such as bar, ball and socket, OT equator and locators. A new attachment system with metal to metal interface named Titach has evolved. During mastication, loads are transferred to alveolar bone surrounding the implants. Objectives: This study was done to compare the stress transmitted to peri-implant tissues of implant-assisted mandibular overdenture using two different attachment designs; Titach attachment and locator attachment. Materials and methods: A completely edentulous epoxy resin mandibular model was used in which two parallel dental implants were inserted at the canine region bilaterally. Sixteen mandibular implant-assisted overdentures were constructed forming two groups; each with different attachment design. Group I received 8 pairs of Titach attachment, while group II received 8 pairs of locator attachment. The difference in stress distribution was measured using strain gauges and compared between the two studied groups. Vertical load and oblique load (30o and 45o) of 50 and 100 N using the universal testing machine were applied bilaterally on the central occlusal fossae of mandibular first molars. Results:There was no significant difference between group I and II upon application of vertical loading 50, 100N and 30o oblique loading 50 N. However, group I showed lower strain values upon application of 30o oblique loading 100N, 45o oblique loading 50N and 100N. Conclusions: Titach attachment with metal to metal interface showed less strain values with favourable stress distribution when compared to zest anchor locator attachment with nylon interface for implant-assisted mandibular overdenture.

The stress that affects structures and their mechanical and geometrical parameters are random values. For that reason, the dependability of a construction facility (technical system) is generally evaluated in terms of the probability of no-failure over the estimated period of operation. The paper shows the feasibility of dependability analysis of building systems in the course of their design using logical and probabilistic methods, presents algorithms for regulating their dependability. It examines the feasibility of assuring the dependability of a construction project using the example of a double-span whole hinged beam. The paper also establishes the requirement of accounting for all possible destruction models of a building system. The dependability of a double-span whole hinged beam is estimated based on the probability of non-occurrence of all possible destruction models or one of a set of possible kinematic mechanisms. A kinematic mechanism forms a chain of plastic hinges or a chain of progressive failures of effective sections. In other words, the task of preventing progressive collapse comes down to ensuring the required dependability of both the building as a whole, and its individual members (effective sections) by adjusting qualitative and quantitative indicators of the dependability structure. The dependability of a member is understood as its ability to maintain internal force within the effective section at least as high as the external force. It is shown that correct design solutions, rational choice of materials and load non-exceedance probabilities enables specified dependability of a building system. In some cases that allows saving materials, in others enables lower probabilities of failure. Constructing the dependability structure of a technical system enables a quantitative estimation of the most hazardous design models of destruction, rational management of the choice of safety factors of load bearing members, redistribution of such safety factors, thus preventing progressive collapse. The introduced differential characteristics of the members’ “weight”, “significance”, “contribution” and “specific contribution” allows demonstrating the distribution of the roles of each member within the specified structure in terms of specific problems, including accounting for the possibility of progressive collapse. The study has shown that the removal of undependable vertical load bearing structures does not solve the problem of dependability of a construction project, including protection against progressive collapse. It has been established that the design of structures, including in terms of considerations of progressive failure, must involve constructing a system dependability structure using kinematic analysis, identifying the most important and significant members of such structure and – using special adjustment techniques – obtaining the required structure dependability. That will enable significant resource saving and reduction of costs associated with the development of construction operations.

The differences in development and situation of karst caves lead to two kinds of karst caves, and the karst cave may be on the pile side or at the pile bottom, which has a different influence on the bearing capacity of pile foundation. The paper presents a numerical analysis of the influence of karst caves at pile side on the bearing capacity of super-long pile foundation in karst areas. According to the size of pile foundation of a real bridge project, this paper modelized karst caves and investigated the karst cave from the effect of length, height, and thickness of roof on horizontal and vertical bearing capacity of pile foundation. The main conclusions can be drawn as: when the horizontal displacement at the top of pile foundation is greater than 0.05 m, the horizontal load is correlated positively with the length of karst cave; when the vertical displacement is greater than 0.07 m, the vertical load is correlated negatively with the thickness of the roof of karst cave. However, the height of karst cave has little effect on the bearing capacity; also the existence of karst cave has little influence on the dynamic response of pile foundation. The results of this study can be important with reference to the design and construction of pile foundations in karst areas.

Prestressed concrete pipe pile with high bearing capacity, the advantages of convenient construction, low cost and widely used in practical engineering, because of the prestressed high strength concrete in use process is in complex stress state, both are under a lot of vertical load, and horizontal seismic action needs to be considered at the same time, it is necessary under the condition of considering the vertical load bearing capacity of prestressed high strength concrete level and considering the loading level, the horizontal bearing capacity. Scholars at home and abroad based on the simple hypothesis, puts forward the calculation method of a lot of interaction with soil, in the future will be adopted in calculation, using ABAQUS finite element analysis, this paper established the three-dimensional finite element model of prestressed concrete pipe pile, respectively under different vertical pressure (P = 4000 kn, P = 4800 kn, P = 6000 kn) one-way load and calculated the horizontal bearing capacity, and under repeated load, respectively to study the size of the different vertical pressure and different reinforcement stirrup ratio on its bearing capacity and seismic performance. The results show that the stiffness of pipe pile decreases significantly with the increase of vertical pressure under different vertical loads. With the increase of vertical load, the ductility and energy dissipation capacity of the components decrease gradually. The horizontal bearing capacity of prestressed high strength concrete pipe decreases with the increase of vertical pressure. However, its amplitude decreases with the increase of vertical pressure value.

One of the major concerns in designing bucket foundations is addressing the effect of the shape of the foundation on deformation. It has not yet been clarified sufficiently how the ultimate load capacity and the deformation up to failure are dependent on the bucket shape, bucket dimensions, loading conditions, and soil properties. Not only for conventional cylindrical bucket foundations, but also for rectangular bucket foundations, in order to adequately design each type of bucket foundation, analytical solutions for the general loadings of both foundations have been urgently needed. In the present paper, analytical solutions are provided by a three-dimensional displacement approach for predicting the deformation up to failure of the soils surrounding cylindrical and rectangular bucket foundations subjected to vertical, lateral, and moment loads in cohesionless soils. The analyses are carried out for nonhomogeneous sandy soils. The lateral stiffness coefficients along the short skirt are presented by extending those along the normal skirt for both cylindrical and rectangular bucket foundations. The lateral yield along the skirt and the compression and shear failures below the base in sand are seen to have a significant influence on the ultimate lateral and moment load capacities of cylindrical and rectangular bucket foundations under vertical loads. Failure envelopes expressed by both ultimate horizontal and moment load capacities under various vertical loads in sand are presented. For cylindrical bucket foundations, as the embedment ratio and vertical load increase, the ultimate lateral and moment load capacities increase. However, for rectangular bucket foundations, the relationships among the ultimate lateral and moment load capacities, vertical load, and embedment ratio are greatly influenced by the breadth ratio. The largest ultimate lateral and moment load capacities among the breadth ratios of rectangular bucket foundations under a certain vertical load depend on the embedment ratio. The ultimate lateral and moment load capacities of square bucket foundations are less than those of cylindrical bucket foundations with the same cross-sectional area. The predicted relationships between the ultimate lateral and moment load capacities and the embedment ratio under various vertical loads are compared with the results obtained from FEM and experiments. The monotonic behavior of the sand surrounding bucket foundations up to failure is elucidated from the relationship between the lateral load and the lateral displacement and that between the moment and the rotation.

Bridge damage often occurs, as a result of damage to the bridge causing financial aspects losses and can also cause fatalities. The causes of the damage various factor, one of which is the bridge structure experiencing fatigue. This fatigue caused the strength of the structure of the bridge to decrease. Bridge damage due to a decrease in the strength of this bridge structure can impact the bridge to collapse. To minimize bridge damage due to a decrease in the strength of the structure of the bridge there is a need for bridge maintenance and to make it easier in terms of maintenance it is necessary to know the pattern of collapse of the existing bridge. In the analysis of this collapse pattern, a waren type steel continous bridge will be modeled with a span length of 120 meters. This analysis is carried out by giving a static vertical load at a reference point on the bridge frame, where the load is increased by multiplying until the structure is demage. The results of the study show that in the waren type continuous steel truss bridge failure occurs at the final portal diagonal element in the 2 middle positions. Based on FEMA 356 displacement target, the level of structural performance shows the bridge model under IO conditions and based on SNI 2833-2008, the actual ductility that occurs has met the requirements.

This paper proposes a composite stability control strategy for tire blowout electric vehicle with explicit consideration of vertical load redistribution, subject to multi-constraints, uncertainty and redundant actuation. To readily implement system state and actuator increment constraints, a model predictive controller is designed to enhance vehicle stability performance and original lane keeping. Meanwhile, a sliding mode control-based longitudinal velocity controller is collaboratively proposed for maintaining the original longitudinal velocity after tire blowout in the freeway, which can reduce considerably the rear-end collision accidents. After that, a constrained weighting least square-based reconfigurable torque distributor is developed to realize the tracking of the virtual resultant yaw-moment and longitudinal tire force signals generated by the above controllers, considering system physical constraints and actuator capability simultaneously. Simulations with different tire blowout scenarios are conducted on the developed dynamic simulation platform to demonstrate the effectiveness of the designed control methods; furthermore, the influence of different tire blowout on the vehicle movement behaviors is discussed. Statistical results based on the system transient performance and control effort evaluating indictors highlight the considerable superiority of the developed model predictive controller compared with the linear quadratic regulator.

This paper compared two approaches used to analyze a modular pedestrian pavement made of hexagonal basalt pavers. In presence of occasional heavy traffic roads, the pavement should be verified using methods currently used for road pavements. Different loading conditions were examined varying the geometry of the blocks, and the magnitude of the vertical load. In all cases, the results obtained from the analytical theory of Westergaard were higher than those obtained from a finite element model (FEM). Therefore, a parametric study was performed in order to use the analytical method as an alternative to the costly FEM approach. The results of comparison gave a correction factor, valid for hexagonal pavers: it permits to analytically estimate with good approximation the stresses induced by heavy loads applied to natural stone blocks.

In order to analyze the deformation and stress characteristics of the pile foundation on the slope, this paper uses the finite element software Abaqus for numerical simulation. The displacement and stress data of pile under different working conditions (the combination of heap load and vertical load and horizontal load and inclined load) were collected; the distribution of pile displacement, axial force and bending moment were analyzed. Simulation results show that: slope top loading has little effect on vertical displacement; when the heap load exceeds 200 kPa, the horizontal displacement is greatly affected. Pile axial force decreases with pile burial depth; pile lateral resistance plays a more adequate role in the rock and soil layer. The bending moment of double pile foundation is positive at the top and negative at the bottom. Applied oblique load has obvious p-Δ effect.

In this paper, a four-layered road structure containing a top-down crack is investigated by performing finite element analyses in ABAQUS. In this study, in addition to the vertical load of a vehicle wheel, the horizontal load as well as its position with respect to the crack is also considered in the analyses, and the crack tip parameters including stress intensity factors (SIFs) and T-stress are then calculated. Moreover, influence of elastic modulus and thickness of the pavement layers on the crack tip parameters is studied. Results show that the horizontal and vertical loads along with their position with respect to the crack, elastic modulus and thickness of the road layers influence the crack tip parameters (KI, KII and T-stress) significantly. It was also found that for the cases that the vehicle wheel is positioned near the crack plane, only the shear deformation mode is observed at the crack tip; while, for the vehicle wheel positions far from the crack, only the opening mode is observed, and between these positions, both the opening and shear deformation modes (i.e., mixed mode I/II) are observed at the crack tip.

Prikazan je proračun nosive zidane konstrukcije. Konstrukcija se sastoji od 3 etaže, prizemlja te 2 kata. Proračun sadrži dokaz nosivosti zidova na vertikalna opterećenja, dokaz nosivosti zidova na potres te proračun potrebne armature na vertikalne serklaže, određivanje širine temeljnih traka iz uvjeta nosivosti, te proračun međukatnih konstrukcija i određivanje potrebne armature, This paper presents the calculation of the load bearing masonry structure. The construction consists of three floors, ground floor and two floors. The calculation contains proof of the bearing capacity of the walls against earthquakes, and the calculation of the necessary reinforcement for the vertical cerclages, the calculation of the width of the foundation strips from the loadbearing conditions, and the calculation of the structures and the calculation of the reinforcement required.

Although there have been many studies on pile foundations subjected to vertical load domestically and externally, the domestic studies on pile under horizontal load have been limited. The purpose of this study is to develop a pile, which allows the pile member and column member to overlap with each other, and the lateral load to be supported not only by a pillar member but also by pile member in order to address the problems above. The results of field load test showed that the horizontal resistance of pile is higher by 4-4.5 times compared to general ones. It was found that the improved horizontal resistance corresponds to the wing area of the upper fixed pile, suggesting that the resistance is proportional to the wing area. The 1/β depth should be considered for the reinforcement against horizontal force to a proper depth.

When connected piles are used as settlement reducers, the proportion of vertical load carried by the pile may come close to the allowable load of the pile. To reduce not only the vertical load, but also the lateral load and bending moment to which the pile is subjected, the disconnected piled raft (DPR) has been introduced as an effective design for the role of the settlement reducers. Although several DPRs have been constructed, most of the research efforts on DPRs are limited to the structural behavior such as the evaluation of the seismic acceleration of the structure on the DPR; thus, there is a need to evaluate the dynamic performance of DPRs focusing on geotechnical problems. In this study, the seismic behavior of DPRs is investigated using dynamic centrifuge tests and compared with the results obtained from connected piled rafts (CPRs). The bending moment of piles of different materials, namely aluminum and steel, is evaluated. Results show that there is a reduction in the amplitude of acceleration of the foundation horizontal motion for the DPR compared to the CPR. The edge pile of a DPR attracts the smaller dynamic bending moment of the pile compared to that of a CPR. The dynamic bending moment of piles is predominantly governed by the soil behavior rather than the pile material. Finally, the seismic behavior of DPR was evaluated comprehensively through centrifuge tests.

Cold-formed steel (CFS) composite exterior walls are made of cold-formed, thin-walled steel lipped channel studs with board linings on both sides. There are limited data on the structural and thermal performance of CFS composite exterior walls under fire conditions, especially from simulation analysis, in contrast with the data available for interior walls. Therefore, a new simplified model was proposed in this paper to accurately simulate exterior walls exposed to fire on one side; in this model, spring elements were applied to provide out-of-plane constraints different from the constraints of the simplified model for interior walls previously proposed. A discussion of the numerical simulation results of studs with different parameters, including temperature-rise curves, vertical load ratios, screw spacings, steel grades and cross-sectional sizes, was conducted to determine the range of the spring stiffness. Finally, the developed model was validated using the fire test results of two CFS exterior walls, where one had an external panel made of oriented strand boards and the other had an external panel made of autoclaved lightweight concrete boards.

Prikaz proračun nosive konstrukcije zidane zgrade. Nosiva konstrukcija je zidana i omeđena serklažima. Međukatna konstrukcija je AB ploča. Građevina se nalazi u potresnoj zoni gdje se očekuje vršno ubrzanje podloge ag=0.2 g s povratnim periodom od 475 godina, II. području opterećenja vjetrom i području D opterećenja snijegom. Proračunom dokazati mehaničku otpornost i stabilnost konstrukcije. Proračun proveden prema europskim normama EC1, EC6, EC8, dopunjeno podacima o opterećenjima prema odgovarajućim hrvatskim normama i pravilnicima., The calculation of the load-bearing structure of a masonry building. The load-bearing structure is masonry and bounded by circles. Floor construction is AB . The building is located in the earthquake zone where the peak acceleration of the substrate is expected ag = 0.2 g with a return period of 475 years, II. wind load area and snow load area D. Prove the mechanical resistance and stability of the structure by calculation. Calculation carried out according to European standards EC1, EC6, EC8, supplemented with data on loads according to the relevant Croatian standards and regulations.

In this paper, using the elastic foundation beam algorithm, the calculation method of internal force of side span of longspan suspension bridge considering self weight is proposed, and the calculation method of side cable sag is also proposed. The internal force calculation method proposed in this paper is simple and fast. This method can check each other with the bridge software calculation method. Nowadays, there is no recognized calculation method of side cable sag in the world, and most of the side cable sag of built bridges are unreasonable values. In this paper, the engineering example of Kanmonkyo Bridge in Japan is taken. The comparative calculation shows that the side cable sag calculation method proposed in this paper is very reasonable, and the bridge designed by this method is safer and more economical.

Bamboo structures have various types of connections, such as bolting and lashing. One crucial issue in bamboo structures is that the connection with bolts and nails has a lower load-carrying capacity associated with the bamboo failure resulting from the bolt or nail invading them. This paper focuses on the connection for raw bamboo members with steel hoops (BHC), of which the two semi-circular steel hoops are fastened to the raw bamboo with high-strength bolts. The sliding friction is controlled by the interfacial pressure, which can be increased by tightening the bolts. A push-out experiment on thirty-six specimens was conducted considering the following two parameters: the different surface conditions of raw bamboo (with or without the epidermis) and the different interfacial pressure. The test results mainly showed the two failure modes of specimens under certain conditions: continuous longitudinal slip after the vertical load reached the peak; and the steel hoop stuck in the bamboo skin after a period of slip. It is found that the sliding friction was controlled by the interfacial pressure, and the difference in the anti-sliding capacity between the epidermal bamboo specimen and the non-epidermal bamboo specimen was magnified with the increase of interfacial pressure. The contact stress on the surface of bamboo is approximately uniformly distributed based on the finite element analyses. The interfacial pressure can be predicted by the torque value of the digital electronic torque wrench and the equations established by mechanical analysis, respectively. Moreover, the design formulae of bearing capacity for BHC under three guaranteed rates (50%, 95%, and 99.9%) were developed based on probability theory, while the fourth design formula was derived by regression analysis. The reliability indices of the four design formulae were up to 0.07, 1.44, 3.09, and 0.97, respectively, and the resistance partial coefficients were suggested accordingly.

Developing technologies capable of constantly assessing and optimizing day-to-day activities has been a research priority for several years. A key factor in such technologies is the use of highly sensitive sensors to monitor in real-time numerous parameters, such as temperature and load. Due to their unique features, optical fiber sensors became one of the most interesting and viable solutions for applications dependent on those parameters. In this work, we present an optical fiber load sensor, called load cell, based on Fabry–Pérot hollow cavities embedded in a polymeric material. By using the load cells in a parallel configuration with a non-embedded hollow cavity, the optical Vernier effect was generated, allowing maximum sensitivity values of 0.433 nm N−1 and 0.66 nm °C−1 to be attained for vertical load and temperature, respectively. The proposed sensor’s performance, allied with the proposed configuration, makes it a viable and suitable device for a wide range of applications, namely those requiring high thermal and load sensitivities.

Prikaz proračun nosive konstrukcije zidane zgrade. Nosiva konstrukcija je zidana i omeđena serklažima. Međukatna konstrukcija je AB ploča. Građevina se nalazi u potresnoj zoni gdje se očekuje vršno ubrzanje podloge ag=0.2 g s povratnim periodom od 475 godina, II. području opterećenja vjetrom i području D opterećenja snijegom. Proračunom dokazati mehaničku otpornost i stabilnost konstrukcije. Proračun proveden prema europskim normama EC1, EC6, EC8, dopunjeno podacima o opterećenjima prema odgovarajućim hrvatskim normama i pravilnicima. The calculation of the load-bearing structure of a masonry building. The load-bearing structure is masonry and bounded by circles. Floor construction is AB . The building is located in the earthquake zone where the peak acceleration of the substrate is expected ag = 0.2 g with a return period of 475 years, II. wind load area and snow load area D. Prove the mechanical resistance and stability of the structure by calculation. Calculation carried out according to European standards EC1, EC6, EC8, supplemented with data on loads according to the relevant Croatian standards and regulations.

Many difficulties arise in organic soils due to low bearing capacity, very high compressibility, and high-water content, challenging engineers and researcher engaging in geotechnical studies. Also, the effects of mechanical disturbance of specimens in obtaining different geotechnical properties of soils are one of the most complex issues in geotechnical studies. The laboratory model tests under vertical load for determining ultimate bearing capacity of footing were carried out on the surface of organic soils to avoid the effects of the sampling disturbance to perform experiments in field condition. Block samples obtained from inspection pit using the big size test box sampler were considered high sample quality according to different methods. In the present study, large-sized undisturbed samples were obtained to determine bearing capacity organic soils. The results of loading tests were compared with results of the empirical methods available in literature, proposed for the prediction of bearing capacity, and two-dimensional finite element analysis results. The undisturbed organic soil samples obtained as natural formations were transported to laboratory for testing, and thereafter the loading tests were carried out on twenty-one box samples. Also, the index and engineering tests were performed on undisturbed samples. The organic soil samples were collected from Kayseri Free Trade Zone and Organized Industrial Zone area of Turkey for this study. Except for the hyperbolic model, the ultimate bearing capacity values obtained with different methods based on the results of experimental investigation are compatible with finite element results and empirical methods.

A half-scale field test was conducted on a pile group installed at a stiff clay site. The pile group consisted of eight steel H-piles, with a battered pile at each corner, and connected to ...

This paper presents a numerical study of the effect of concentric inclined loading on the undrained bearing capacity of stone column group. The stone columns are arranged in a group of four columns with toe sitting on a hard stratum. A rigid square footing is placed on top of the stone columns. The soft soils and the stone columns are modelled as linear-elastic perfectly plastic material with non-associated flow rule. In this study, the area replacement ratio varies from 0.2 to 0.5 and the load inclination angle varies from 0° to 45°. The numerical results are first compared with the limit analysis for both non-reinforced foundation and a stone column reinforced foundation under vertical load. Subsequently, an analysis is carried out for cases with inclined load. Based on the results, a prediction equation is developed to estimate the modified bearing capacity factor for stone columns with inclined loads. The effect of embedment depth on bearing capacity is also investigated. The failure mechanism for stone column group is identified and found to extend deeper and larger compared to non-reinforced foundation. The inclined load has caused the failure surface to be altered and tilted.

Layered and jointed rock masses are common in underground environments. Honest stability analysis of such rock masses requires the application of discrete element methods, since other methods of analysis are either continuous by nature (FEM), or limited to two block interaction (Voussoir model). In this paper the stability of jointed rock layers is studied using DDA. Two different configurations are studied: 1) single layer-immediate roof; 2) multi-layered roof. The influence of joint spacing and shear strength is inves- tigated and different failure modes are discussed; the kinematics and evolution of deformation are studied in depth. For a single layer configuration it is shown that stable arching is achieved when the shear resistance along joints is sufficient to inhibit inter-block shear and to induce block rotation at the abutments. For a multi- layered configuration it is found that the transition from unstable multi-layer deflection due to vertical load transfer, to stable arching is marked by reduction of differential deflections and homogenization of displace- ment within the stack of layers. The numeric solution is compared with the semi-analytical Voussoir solution, which for the given rock mass structure and mechanical properties, is found to be un-conservative.

Objective An assessment was performed to identify and evaluate dental enamel wear caused by monolithic zirconia restoration. Literature searches were conducted in PubMed, Science Direct, Cochrane Evidence, and the Cochrane Library up to May 2020. Material and methods Studies were selected for systematic review according to the inclusion (articles conducted on the wear of enamel samples opposing monolithic zirconia) and exclusion (case reports, non-English articles, and monolithic zirconia samples facing other materials rather than human enamel) criteria. Of those, articles on polished and glazed monolithic zirconia subjected to a 50 N vertical load with a range of 240,000-250,000 cycles, equivalent to 1 year of in vivo mastication, were included in the meta-analysis. Results In total, 3968 articles were pooled. Twenty-five articles met the inclusion criteria for the systematic review. Three studies were included in the meta-analysis. The results showed that the enamel wear against monolithic zirconia was within the statistically accepted level. Moreover, the polished monolithic zirconia surface caused less enamel wear than the glazed surface. Conclusion This review indicates that monolithic zirconia restorations cause acceptable antagonist enamel wear. Moreover, the meta-analysis results agreed that the final restoration's surface texture plays an essential role in the wear process. Clinical significance Monolithic zirconia restorations have been widely used in dental practice because they eliminate the chipping problems resulting from using veneered restorations. With recent technology development, monolithic zirconia has obtained more esthetic features and a more natural look. However, due to the high strength and surface roughness of monolithic zirconia, wear on the antagonist's teeth was detected. The results showed that this wear amount was statistically acceptable and lower than other ceramics such as feldspathic porcelain and enamel. Furthermore, surface treatment methods must be applied to minimize tooth wear, as polished or glazed surfaces interfere with enamel loss.

Study design Finite element analysis. Objective To determine and compare the biomechanical stability of the bicortical short C2 pars screw fixation for high-riding vertebral artery (HRVA) with the C2 pedicle screw and C2 translaminar screw fixation in finite element models. Summary of background data Fixation of C2 is technically demanding in the case of HRVA. However, there is no consensus on the alternative technique for the C2 screw fixation for HRVA in the literature. Methods A finite element (FE) model of the upper cervical spine (C0-C2) with HRVA had been developed. C1 pedicle screw was applied at C1 by using notching technique. Bicortical short C2 pars screws, C2 pedicle screws, and C2 translaminar screws were used in each model. Then a vertical load of 50 N and a 1.5 Nm torque were applied to the C0 to simulate flexion, extension, lateral bending, and axial rotation respectively. Results Compared with C2 pedicle screw fixation, the bicortical short C2 pars screw fixation increased the range of motion (ROM) by -1.45%, 2.13%, 62.0%, and 22.0% under flexion, extension, lateral bending, and axial rotation, respectively; However, the C2 translaminar screw fixation increased the ROM by 43.6%, 17.8%, 423.4%, and 19.9%, respectively. In terms of the peak von Mises stress, compared with C2 pedicle screw fixation, bicortical short C2 pars screw decreased 46.1%, 41.6%, 71.3%, and -12.5% under flexion, extension, lateral bending, and axial rotation, respectively; C2 translaminar screw decreased -2.66%, -4.87%, 73.0% and -10.1%, respectively. Conclusion For a patient with HRVA, bicortical short C2 pars screw fixation provides sufficient stability and exhibited a smaller von Mises distribution on the screw-rod construct, indicating it could be an effective C2 internal fixation method for HRVA to promote C1-C2 stability and avoid the vertebral artery injury.Level of Evidence: N/A.

This paper presents an experimental assessment into the behaviour of fire-exposed reinforced concrete (RC) beam–column joints with different reinforcement anchorage details subjected to exterior column removal. The thermal response of the RC joint specimens is firstly described, including the development of the temperature fields and the horizontal restraint forces throughout the fire tests as well as the cooling-induced cracking patterns. Subsequently, within the following displacement-controlled push-down tests, the vertical load and horizontal reactions are also monitored. The mechanical behaviour of the test specimens is discussed in detail and a full account of the observed failure modes is provided. Particular attention is given to comparing the experimental axial-moment strength interaction curves with theoretical predictions in order to examine the underlying behavioural mechanisms, with emphasis on the influence of the fire conditions as well as varying anchorages details. Overall, this study provides not only reliable data for the validation and calibration of future numerical and analytical studies, but also forms the basis for practical design of fire-exposed RC frame structures against progressive collapse.

This paper is presented the lateral dynamic response of pile groups embedded in dry sand under influence of vertical loads and the pile shape in-group, which are subjected to the lateral two-way cyclic loads. The laboratory typical tests with pile groups (2×1) have an aluminum-pipe (i.e. circular, square) pile, embedded length to diameter of pile ratio (L/D=40) and spacing to diameter ratio (S/D) of 3, 5, 7 and 9 are used with different cyclic-load ratio (CLR) 0.4, 0.6 and 0.8. The experimental results are revealed that both the vertical and lateral pile capacity and displacement is significantly affected by the cyclic-loading factors i.e. (number of cycles, cyclic load ratio, and shape of pile) .In this study, important design references are presented. Which are explained that the response of the pile groups under cyclic lateral loading are clear affected by the attendance of vertical load and pile shape. Where, it is reduction the lateral displacement of group piles head and increase lateral capacity about (50) % compared without vertical loads. On the other side, the pile shape is a well affected to the pile response where the level of decline in lateral displacement at the pile groups head in the square pile is more than circular pile about 20 % at the same load intensity.

Made available in DSpace on 2019-10-03T17:31:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-08-01. Added 1 bitstream(s) on 2019-10-04T16:20:51Z : No. of bitstreams: 1 S1983-41952019000400884.pdf: 2851790 bytes, checksum: ebaa6507d00b6e0104e34d8fb682dfdf (MD5) Resumo Vigas são submetidas à flexão e cisalhamento, sendo esse último esforço o tema desta pesquisa. O objetivo deste trabalho é analisar especificações para dimensionamento ao esforço cortante de vigas de alvenaria estrutural em blocos de concreto, a partir de extensa avaliação da literatura e de ensaios experimentais aqui relatados. A partir desse escopo, são sugeridas especificações para revisão da normalização brasileira. Na parte teórica, foram considerados trabalhos anteriores tanto nacionais quanto internacionais e as prescrições das normas brasileiras NBR15691-1/2011 e NBR 6118/2014, além da norte-americana, australiana, canadense e europeia, TMS 402/2016, AS3700/2001, CSA S304/2014 e EuroCode 6.1/2001, respectivamente. Com intuito de analisar e validar as especificações da literatura foi realizado um programa experimental de análise de dez vigas de alvenaria com blocos de concreto submetidos principalmente ao esforço cortante. Foram consideradas vigas de duas fiadas, três posições da carga vertical, variando a/d, e duas taxas de armadura transversal. Na análise dos ensaios verificaram-se semelhanças no comportamento último das vigas de alvenaria armada com a teoria proveniente das vigas de concreto armado, com algumas particularidades de fissuração na região das juntas de argamassa. Além disso, as especificações estabelecidas pela norma brasileira e europeia levaram a resultados consideravelmente maiores do que os resultados experimentais, enquanto que os presentes nas normas TMS 402/2016, AS3700/2001, CSA S304/2014 e NBR6118/2014 levam a resultados próximos aos obtidos experimentalmente. Como conclusão pode-se destacar que o padrão de ruptura é semelhante ao esperado para vigas de concreto armado, as fissuras foram condicionadas pela posição do ponto de aplicação do carregamento e pelas juntas de argamassa, o aumento da taxa de armadura transversal levou ao aumento da força cortante de ruptura. Os resultados indicam não ser consistente a consideração de aumento aparente da resistência ao cisalhamento pela relação M ⁄ (V∙d). Eliminando-se essa recomendação, considerando a resistência da alvenaria igual a 0,35 Mpa, limitando a tensão nos estribos a 0,90 de fyk e considerando a contribuição da armadura longitudinal, foi possível estimar o valor de cortante na ruptura de cada viga entre 73% a 106% dos valores verificados nos ensaios. Abstract Beams are subject a flexure and shear, with the last as the theme of this research. The purpose of this paper is to analyze specifications for the shear design of concrete block structural masonry beams, based on an extensive literature review and experimental tests here reported. From this scope, specifications for revision of Brazilian standardization are suggested. In the theoretical part, literature review from both national and international researchers were considered and the specifications of Brazilian standards, in addition to North American, Australian, Canadian and European, ABNT NBR 15961-1/2011, ABNT NBR 6118/2014TMS 402/2016, AS3700/2001, CSA S304/2014 and EuroCode6.1/2001, respectively. To analyze and validate the specifications of the literature, an experimental program was carried out assessing ten concrete block masonry beams results tested mainly to shear loads. Two-course high beams with three vertical load positions (position a/d) and two transverse reinforcement rates were tested. The specifications from the Brazilian and European standards led to considerably higher results than the experimental results, while those presented in the standards TMS 402/2016, AS3700/2001, CSA S304/2014 and NBR6118/2014 lead to results close to those obtained experimentally. As a conclusion, it can be noted that the rupture pattern is similar to that expected for reinforced concrete beams, the cracks were conditioned by the position of the loading point and by the mortar joints positions, the increase in the transverse reinforcement ratio led to an increase in the shear force. Results indicate that the consideration of apparent increase in shear strength by the ratio M ⁄ (V∙d) is not consistent. Eliminating this recommendation, considering the masonry shear strength equal to 0.35 MPa, limiting the stirrups tension to 0.90 of fyk and considering the contribution of the longitudinal reinforcement, it was possible to estimate the shear value at the rupture of each beam between 73% to 106% of the values verified in the tests. Universidade Federal de São Carlos Departamento de Engenharia Civil Universidade Estadual Paulista Departamento de Engenharia Civil Universidade Estadual Paulista Departamento de Engenharia Civil