Floor Displacement Research Articles

A Single Session of Temporomandibular Joint Soft Tissue Therapy and Its Effect on Pelvic Floor Muscles Activity in Women-A Randomized Controlled Trial.

Background/Objectives: Pelvic floor muscles (PFM) play a vital role in the proper functioning of the pelvic and abdominal organs. The PFM are structurally connected to other areas of the body, forming part of the deep front line. Due to its course, this line connects the PFM with the temporomandibular joint (TMJ). The aim of the study was to evaluate the impact of a single 15-minute soft tissue therapy session in the TMJ on the activity of the PFM. Methods: A total of 47 nulliparous women aged 20-29 years old diagnosed with myofascial pain in the TMJ area were included in the study. PFM were assessed using the Noraxon Ultium device and a vaginal probe, utilizing the surface electromyography (sEMG) method. The sEMG signal was processed with MyoResearch XP software version 1.0. Additionally, bladder floor displacement during PFM contractions was evaluated using an ultrasound imaging device set in B-mode (LOGIQ P7/P9). Results: In the experimental group, following the applied soft tissue therapy, a significant decrease in resting PFM activity between maximal contractions was observed (p < 0.05). The resting PFM activity assessed in the final phase of the measurement protocol was also significantly lower (p < 0.05). During endurance contractions in the experimental group, after the therapy, an 18.05% increase in PFM tension amplitude was noted, although this change was not statistically significant. In the control group, a decrease in amplitude was observed during the second assessment in this phase of the test. Conclusions: A single session of soft tissue therapy in the TMJ area may enhance the ability of the pelvic floor muscles to relax and contribute to improved muscle function by increasing their activation levels during submaximal contractions.

Evaluation of seismic demands for adjacent irregular buildings with transverse alignment eccentricity

Seismic pounding occurs when adjacent buildings lack adequate spacing, exacerbated by Alignment eccentricity and horizontal irregularities of adjacent buildings. The seismic lateral oscillation of adjacent irregular buildings promotes a torsional response under earthquake excitation, moreover, the gap distances recommended in the regulations to prevent collisions are generally insufficient due to the pounding behavior complicated by irregularity of adjacent buildings. Hence, this research aims to evaluate the eccentric pounding effects on seismic response demands for adjacent irregular buildings with transverse alignment eccentricity. The displacement, inter-story drift, story shear force, and torsional rotation responses are investigated and compared for different levels of irregularity. Results findings reveal that increasing alignment eccentricity of adjacent buildings leads to greater lateral displacements in the rebound direction, reduced displacements in the impact direction, and increased torsional rotation of the buildings, consequently, promote eccentric pounding, higher eccentricity leads to greater horizontal floor displacements and twisting motions, which increases the chances of adjacent floors colliding.

NUMERICAL ERROR METHOD TO DETERMINE THE EFFICIENCY OF REDUCING VIBRATIONS DUE TO EARTHQUAKE LOADS ON BUILDINGS USING FLUID VISCOUS DAMPER

According to The Indonesian Earthquake Map, Padang City in West Sumatra is in Earthquake zone 6. This indicates that Padang City is very vulnerable to earthquakes. Meanwhile, developments in the construction of high buildings also continue to show progress all the time. The main problem that is often faced is the issue of structural damage due to earthquakes. Efforts are needed in earthquake engineering on buildings so that collapse can be minimized. The earthquake damping system used is FVD (Fluid Viscous Dampers) with different types. The Type-A damper is FVD-750 kN and the Type-B damper is FVD-1000 kN, and without using a damper. This research aims to analyze the efficiency of reducing earthquake loads such as floor displacement and vibration period of an 18-story building structure 18 meters high from the base.The analysis method used is a numerical method by calculating earthquake load reduction based on numerical error analysis from the two types of dampers used on structures without using dampers. Building planning refers to SNI 1727-2013, SNI 1726-2019, and SNI 2847-2019, and is assisted by ETABS software. Based on SNI 1726-2019, earthquake risk category II, soft soil condition type (SE), earthquake acceleration response value SDS = 0.745g and SD1 = 0.784g are obtained. The earthquake load used is a dynamic load, taking into account that the condition of the building is irregular. Based on the results of the analysis, it was found that the displacement between floors using the Type-AFVD Damper could reduce the displacement by up to 45.72% and with the Type-B FVD Damper it could reduce the displacement by up to 92.72%. Meanwhile, the period of vibration natural using a Type-A FVD Damper can be reduced by up to 12.34% and using a Type-B FVD Damper can be reduced by up to 33.21%.

Investigation of pelvic floor influence on prostate displacement in image-guided radiotherapy.

The uncertainty of target location during prostate cancer radiotherapy plays an important role in accurate dose delivery and radiation toxicity in adjacent organs. This study analyzed displacement correlations between the prostate and pelvic floor. We retrospectively analyzed registration results from 467 daily cone-beam computed tomography (CT) in 12 patients with prostate cancer who received radiation therapy. We analyzed prostate displacement and the pelvic floor relative to the pelvic bone's anatomy in the translational and rotational directions and identified statistical correlations. The systematic (Σ) and random (σ) displacements of the prostate in the three translational directions, anterior-posterior (AP), superior-inferior (SI), and right-left (RL), were 1.49 ± 1.45, 2.10 ± 1.40, and 0.24 ± 0.53 mm, respectively, and in the rotational directions of the pitch, roll, and yaw were 2.10 ± 2.02°, 0.42 ± 0.74°, and 0.42 ± 0.64°, respectively. The pelvic floor displacements were 2.37 ± 1.96, 2.71 ± 2.28, and 0.47 ± 0.84 mm in the AP, SI, and RL directions, respectively, and 0.93 ± 1.49°, 0.98 ± 1.28 °, and 0.87 ± 0.94° in the pitch, roll, and yaw directions, respectively. Additionally, there were statistically significant correlations between the displacement of the prostate and pelvic floor in the AP and SI directions, with correlation coefficients (r) of 0.74 (p < 0.001) and 0.69 (p < 0.001), respectively. The movement of the pelvic floor may be an important factor that causes prostate displacement, affecting the accuracy of radiotherapy. Therefore, it is necessary to take appropriate measures to ensure that the pelvic floor muscle tension is as consistent as possible in the treatment' CT scan and daily treatment.

Rehabilitation of steel structures using innovative brace members equipped with YSPD damper

Earthquakes are serious risks to human life and infrastructure. An earthquake's influence on human life and its socioeconomic consequences highlight the need to investigate and create the most efficient and easily adaptable ways to minimize losses. The basic concept of different control mechanisms used for protecting structures from the destructive impacts of earthquakes is to dissipate the energy efficiently, therefore ensuring that the structure remains undamaged or sustains minimum damage. To achieve this purpose, the passive control mechanism is a particularly suitable and reliable technology as it doesn't rely on external power to actively dissipate energy. The present study proposes using a passive energy dissipation device called the Yielding Shear Panel Device (YSPD) for strengthening the current steel structures. The YSPD consists of a square hollow section (SHS) that houses a diaphragm plate. The fundamental concept of the YSPD involves harnessing the lateral deformation of a steel plate to absorb and disperse the seismic energy. The Bouc-Wen-Baber Noori (BWBN) material has been used for simulating the hysteresis force-deformation relationship of YSPDs by pinching. YSPDs are simulated as spring components that connect between the beam and the V-brace. A nonlinear time history dynamic analysis was performed to assess the alteration in the structural capacity with the setting up of YSPDs. The performance of the tested structure was assessed considering story drift, story displacement, story shear, column shear, and YSPD hysteresis loops. The results indicated that YSPD installation has improved the structure's capacity. However, the use of dampers resulted in significant drift in all stories, a reduction in total floor displacement, and a decrease in the shear force of the stories. However, the results demonstrated that the YSPD dampers effectively absorbed energy and exhibited stable hysteresis loops.

Parametric Analysis of Moment-Resisting Timber Frames Combined with Cross Laminated Timber Walls and Prediction Models Using Nonlinear Regression and Artificial Neural Networks

The light weight and moderate stiffness of multistorey timber buildings make them susceptible to increased lateral displacements and accelerations under service-level wind loading. Therefore, the fulfilment of serviceability requirements is a major challenge. In this study, linear elastic finite element analysis was used to perform a parametric study of moment-resisting timber frames combined with cross laminated timber walls. In the parametric study, various mechanical and geometrical parameters were varied within practical ranges. The results of the parametric study were used to derive simplified analytical expressions and to train artificial neural networks which can be used to estimate fundamental frequency, mode shape, top floor displacement, maximum inter-storey drift, and wind-induced acceleration. The analytical expressions and the artificial neural networks can be used for the preliminary assessment of serviceability performance of moment-resisting timber frames with and without cross laminated timber walls, under service-level wind loading.

Comparison of a 10-Story Tunnel Formwork Structure with Different Soil Classes According to the 2018 Earthquake Regulations

In this study, elastic design spectra were defined and compared for a 10-story tunnel formwork structure based on different soil types according to the new earthquake regulations implemented in March 2018. The tunnel formwork project used in the comparison was obtained from a static project author in Istanbul Esenyurt. Earthquake data affecting the design were selected for soil classes ZA, ZB, ZC, ZD, and ZE using coordinates 41.0114327 latitude and 28.676468 longitude from AFAD. Earthquake loads were applied in both X and Y directions to the building under consideration. The maximum relative floor displacements, overturning moments, and base shear forces in the structure were obtained using earthquake data for the ZC soil class.

TransFrameNet: A transformer-based approach for generalized seismic performance prediction of building structures

Performing nonlinear seismic analysis on a large number of building structures is challenging. Deep learning offers rapid prediction but still with limitations. One model is generally only applicable to a specific building structure and not easily extended to others. To address this, TransFrameNet, a new method based on Transformer, is proposed. By converting buildings into archetypes, TransFrameNet is able to consider the variations of different buildings in geometric features and component sizes. With hard parameter sharing, multi-task learning further expands the applications for multiple building structures with different designs. TransFrameNet is tested on 100 steel moment resisting frames (SMRFs) to predict floor displacement response using 40 seismic ground motions. Results reveal that TransFrameNet can accurately predict the displacement response of different buildings, with an average mean squared error of 0.0037. Notably, compared to LSTM and Transformer models, TransFrameNet shows significantly improved correlation when tested on a 20-story SMRF structure.

Analysis of industrial floor damege and deformation on a expansive slag

The paper discusses an industrial floor that was constructed on a reactive slag subbase. Five years after completion, the user reported damage caused by floor displacement. Cracks and scratches were observed in the finishing layers, particularly at the connection between the partition walls and the floor. Geotechnical and surveying investigations were carried out to determine the cause of the damage. The investigations revealed the presence of reactive slag as the subbase layer. Floor displacement measurements were taken over a four-year period, from November 2019 to November 2023. Despite being ten years since construction, uplift continues to occur. The average annual increase in displacement for the entire floor over the past three years is 6 mm, with a maximum displacement of 80 mm at the midpoint of the floor. The ongoing increase in displacement and damage makes repairing the building and maintaining its use impossible. Microscopic examinations and geodetic measurements do not indicate a stopping of the expansion processes of the subbase.

Practice-oriented numerical model for seismic response of cold-formed steel-framed mid-rise buildings

Cold-formed steel (CFS) framed buildings are becoming increasingly common, notably in the high seismic regions of the United States (US). However, research to understand the seismic performance of CFS-framed buildings specifically using large-scale (building-level) specimens has begun only recently. Therefore, efforts to validate and improve numerical modeling of whole building systems have been limited due to this lack of experimental data. A recently completed experimental program, conducted at the Large High-Performance Outdoor Shake Table at the University of California, San Diego, involved earthquake testing of a full-scale 6-story CFS-framed building. The test building adopted an assembly of continuous tie-rod and built-up compression stud pack at the ends of individual shear walls to resist seismic overturning moment and uplift forces within the building. The objective of this paper is to present a practice-oriented phenomenological finite element modeling approach intended for design engineers and compare the predictions from this model against the measured seismic response of the 6-story building. The model aims to provide a robust, yet computationally efficient approach, with minimal degrees-of-freedom, while also capturing the salient features of seismic response of mid-rise CFS-framed buildings suitable for nonlinear time history analyses-based design. The building model, developed within the OpenSeesPy finite element platform, includes the shear walls and gravity walls as well as the lateral strength and stiffness contribution from exterior and interior gypsum sheathing. The continuous tie-rod system is also modeled to capture the cumulative floor displacements caused by the axial elongation in the steel rods. The effect of built-up compression stud packs on the lateral behavior of a shear wall was estimated using available experimental data and a detailed numerical model of an isolated shear wall, then subsequently incorporated in the nonlinear hysteretic material model. The numerical model captured the natural frequencies of the translation modes of the building in its undamaged state with <3% error. It also predicted the peak roof drift ratio within an error of 0.03% drift ratio under the design earthquake event. These results provide confidence in the proposed numerical modeling approach as a tool for seismic response prediction of mid-rise CFS-framed buildings with similar structural detailing features.

Seismic performance impacts of staircases in reinforced concrete frame structures under rarely occurred earthquake

Existing research data has been confirmed that the impact of stairs on the overall structure cannot be ignored under the action of earthquakes. To further evaluate the influence of staircases on the seismic resilience of reinforced concrete (Abbreviated as RC) frame structures designed according to Chinese design specifications during infrequent earthquake occurrences, a dynamic elastic-plastic analysis method was utilised. Differences in parameters such as period, vibrational modes, interlayer displacement angle, and base shear force were explored between structures with and without staircases. Data comparisons revealed that, in contrast to frame-only structures, structures with staircases exhibited reduced interstory displacement angles, floor displacement, and floor shear force under lateral loads, with the maximum reduction amplitude being 1.76%, 0.7%, and 1.82%, respectively. Such findings suggest that staircases enhance the lateral stiffness of the structure, thereby bolstering its seismic performance. Furthermore, it was observed that the variance in seismic performance attributed to staircases diminished as the number of storeys increased. The above research results can provide some reference for how to consider the influence of stairs in concrete structures.

Development of Fragility Curves and Assessment of Mass Irregular Structures with Fixed Base and Base Isolated Under Multiple Earthquakes

ABSTRACT Structures are usually built to withstand the mainshock, aftershocks offer extra difficulties. Aftershocks frequently occur following an earthquake result in multiple earthquakes, therefore they are not isolated events. Due to damage advancement, and stiffness and strength deterioration, a damaged structure might collapse under a multiple earthquakes. Based to a probabilistic perspective, the current study investigates the effect of multiple earthquakes on the likelihood of buildings to collapse. This study’s primary objective is to determine how multiple earthquakes affect fixed- and base-isolated structures. In this context, recorded 14 single and 7 multiple earthquakes with various properties were used to examine and assess three-dimensional reinforced concreteframes with four-storey, having fixed base and isolated base. Dynamic analysis, of the three-dimensional structures are carried out in SAP2000. Fragility curves for fixed base and base isolated structures were produced using the incremental dynamic analysis approach. To find the effect of mass irregularity due to single and multiple earthquakes, mass irregularity is placed at every floor level in each structure. The results are compared in terms of floor displacements, floor accelerations, storey drift, base shear, residual displacement, and probability of collapse for fixed base and base isolated structures. The findings highlight the importance of analyzing the structures subjected to multiple earthquakes. The probability of collapse is reduced for mass irregular structures with base isolation in comparison with fixed base structures, when subjected to multiple earthquakes. The designer’s should select base isolation over the fixed base system when the building’s location may suffer multiple earthquakes more frequently.

Estimation of consistent absolute acceleration and relative displacement floor response spectra in existing masonry-infilled reinforced concrete buildings

Estimation of consistent absolute acceleration and relative displacement floor response spectra in existing masonry-infilled reinforced concrete buildings

Seismic Response Analysis of Steel Structure Isolation System Under Long-Period Seismic Motion

To analyze the seismic response of steel structure isolation systems under long-period seismic motion, a 9-story steel frame building was selected as the subject. Five steel structure finite element models were established using SAP2000. Response spectrum analysis was conducted on the seismic motion to determine if it adhered to the characteristics of long-period seismic motion. Modal analysis of each structural model revealed that the isolation structure significantly prolonged the structural natural vibration period and enhanced seismic performance. Base reactions and floor displacements of various structures notably increased under long-period seismic motion compared to regular seismic activity. Placing isolation bearings in the lower part of the structure proved more effective under long-period seismic motion. In seismic design engineering, it is essential to consider the impact of long-period seismic motion on structures and the potential failure of isolation bearings.

A Parametric Study on Composite G+8 Structure With Application of Damper on Different Locations Using Time History Analysis

Abstract: The world's population has been growing quite quickly in recent years. Major cities, in particular, have relatively dense populations, which has increased demand for new homes. Because there isn't enough land for new construction in the majority of the old cities, high-rise buildings are moving into mountainous areas. These days, there is more competition to build high rise buildings all over the world as a result of certain developed nations building extremely tall skyscrapers to demonstrate their power and technology to the rest of the world. Buildings on sloping terrain, however, have different structural configurations than those on level terrain, which causes them to vibrate more during earthquake-induced ground motions, resulting in higher displacements and shears. Increased floor displacement results in damage to the structural components, rendering the structure unusable or, in the worst situation, collapsing as a whole. Reducing the amount of seismic energy that enters slanted ground buildings is essential to preventing damage. This can be done by absorbing the majority of the vibrations that an earthquake produces. There are numerous ways to lessen a structure's seismic reaction, including base isolation, shear walls, bracings, dampers, and more. Because of their effectiveness and simplicity of usage, damping devices are particularly well-liked among these methods. The eight-storey building model with four distinct cases—bare frame, bare frame with damper on corners, bare frame with damper on Central Bay, and bare frame with damper on Alternate Bay—is taken into consideration in this research examination. For modeling, use ETABS 2016 Ultimate programme. Utilize time history analysis as well to investigate how earthquake loading affects structures

Study on the Damping Efficiency of a Structure with Additional Viscous Dampers Based on the Shaking Table Test

This study specifically focuses on the damping efficiency of a damped structure with additional viscous dampers. A two-layer steel frame structure with eight sets of viscous dampers is used to conduct a series of seismic simulation shaking table tests, including a non-damped structure without dampers and two damped structures with dampers placed at 1/2 and 1/6 of the beam span, respectively. By conducting these tests, the energy dissipation, force, and displacement of the damper, as well as the parameters of the structure such as floor displacement and acceleration, are obtained. The main damping efficiency indicators of the damped structure are calculated, including the additional damping ratio, inter-story displacement utilization rate, as well as the reduction rate of the vertex displacement and the base shear relative to the non-damped structure. The study shows that the viscous dampers exhibit full hysteresis loops and a strong energy dissipation capacity in the structure. The seismic response of the vertex displacement and base shear in the damped structure is significantly smaller than that in the non-damped structure. Under different seismic levels, including frequent earthquakes, occasional earthquakes, and rare earthquakes, the damping effect of the dampers placed at 1/2 of the beam span is significantly better than that placed at 1/6 of the beam span. For example, the additional damping ratio for the X-direction artificial wave REN is 19% and 11%, 20% and 13%, and 13% and 11%, respectively. The patterns for inter-story displacement utilization ratio, reduction rate of the vertex displacement, and reduction rate of the base shear are similar. The research findings strongly indicate that the damped structure with additional viscous dampers exhibits excellent damping efficiency. In future damping design, designers need to fully consider the placement of viscous dampers within the beam span.

The effect of sand-crumb rubber mixture treatment on the seismic response of a low-rise building located on liquefiable soil

One of the most effective measures to reduce earthquake risks in high-seismic areas is to reduce the input forces caused by earthquakes to the structure. The properties of rubber materials in geotechnical projects are energy absorption, dynamic deformation change as well as damping of latent energy in loads, high shear modulus and damping ratio, easy access and their economic nature. In this research, with finite difference modeling, the effect of using sand- crumb rubber layer on the seismic behavior of the model has been obtained. In the following, by changing the thickness and depth of the sand-crumb rubber layer, the seismic behavior such as floor displacement and internal forces have been investigated. This research numerically models liquefaction (UBCsand with FLAC) and predicts the effects of the sand-crumb rubber layer of different thicknesses (as % weight of the mixture) under the foundation and evaluates the structure's damage and settlement interacting with the soil by validating the numerical model with the laboratory model and calibrating it with different ratios. The results show that liquefaction, pore water pressure excess ratio and soil settlement will be significantly reduced with the presence of sand-crumb rubber layer, and also the base shear has shown an increase, but the structural damage is reduced.Graphical

Steel structure design and analysis of a modern extreme sports center

A modern extreme sports center consists of a three-story main structure and ancillary structures. The overall architectural shape is simple and elegant. In order to ensure that the center has the high strength, earthquake resistance, corrosion resistance and other characteristics required for extreme sports venues, while taking into account comfort and aesthetics, the building structure adopts a steel frame structure system. This article uses the PKPM2021-V2.1.1.1 version software to conduct an overall calculation and analysis of this steel structure project, and checks the floor displacement calculated by the elastic method under the action of wind load or frequent earthquake standard values. The results show that the vertical structure of this structure is The deformation of the axial members meets the requirements of the code; the displacement ratio and inter-story displacement ratio of the structure under the action of specified horizontal seismic forces considering the influence of accidental eccentricity are checked, and the results show that the structure does not belong to torsional irregularity; the overturning resistance of the structure is checked and The shear-to-weight ratio was calculated and the results showed that the stability of the structure met the specification requirements. It can be seen from the above calculation and analysis that this structure can meet the specification requirements under various working conditions, and the structural design is safe and reliable.

Comparing seismic performances of single-span RC frames with and without wing wall retrofitting by shaking table tests

It is necessary to retrofit existing single-span reinforced concrete (RC) frames which could not meet the current seismic codes due to lack of multiple seismic lines of defence. Adding wing wall is one of the retrofit method that can improve the redundancy of single-span RC frames. To study the effectiveness of single-span frames retrofitted by wing walls, shaking table tests were conducted on two 1:5 specimens to compare the seismic behaviour of single-span RC frames with and without wing wall retrofitting. First, a retrofit scheme for the frame using wing walls was selected. Two specimens—a single-span RC frame and an identical frame with a wing wall retrofit—were placed on the same shaking table board and tested simultaneously. Contrast tests were conducted for 20 earthquake cases. The main conclusions are as follows: (1) Adding wing walls to a single-span frame in bi-direction is a reasonable strengthening scheme. (2) For the single-span frame without retrofitting, cracks appeared in the early stages and rapidly developed, forming plastic hinges at the ends of the beams and columns. For the single-span frame with retrofitting, cracks first appeared in the construction joints between the wing walls and beams, and then extended to wing walls and beams. The test phenomena indicate that adding wing walls to a single-span frame can increase system redundancy, and act as the first anti-seismic line of defence. (3) From the measured data, it is shown that adding wing walls to a single-span frame can improve its seismic capacity and control the lateral deformation. The peak floor displacement response of the retrofitted frame reduced by 30%–40% compare with that of the frame without retrofitting. (4) When input PGA was 0.15g (design based earthquake), slight damage occurred to the frame retrofitted by wing wall, while damage of the frame without retrofitting was moderate. When input PGA was 0.30g (rare earthquake), moderate damage occurred to the frame retrofitted by wing wall, while damage of frame without retrofitting was severe. Therefore, adding wing walls is an effective method for retrofitting single-span RC frame structures.

Investigating the Displacement of a Structure Equipped with Rotational Friction Damper: Considering the Structure-soil Interaction Effect

In this research, the effect of soil and structure interaction is investigated in a structure equipped with rotational friction dampers, with several earthquake records and two types of soil. It was modeled in SAP 2000 software and analyzed under the nonlinear dynamic analysis of the time history with the records of the San Fernando, Northridge, and Imperial Valley earthquakes. The used soil was considered relatively "hard" and relatively "soft" soil based on two types of two and three soil groups based on the 2800 regulation.&#x0D; In this research, the soil and structure complex was subjected to the effect of three earthquake records, and after the vibration, the parameter, and the lateral displacement on the desired structure were investigated. Based on the obtained results, it can be said that the displacements in the structure with the damper have been significantly reduced and also the soil interaction effect is minor in type two or hard soils, while the analysis with the interaction effect in a soft soil It has a significant effect on the displacement of the structure, also the rotational friction dampers were able to reduce the displacement of floors and drift in both types of soil. For this reason, the structure was analyzed in two different soil types with damper and with interaction effect, with damper and without interaction effect, without damper and with interaction effect and without damper and interaction effect, in general, it can be said in soft soil. Damping of the soil has a significant role in reducing the forces and deformations of the frame. The effect of the interaction between the soil and the structure in the structures whose underlying soil is soft should be subjected to nonlinear dynamic analysis.