Seismic Strengthening of Existing RC Buildings With External Cross-Laminated Timber (CLT) Walls Hosting an Integrated Energetic and Architectural Renovation

In this study a timber-based integrated solution is presented to solve at once common issues affecting typical reinforced concrete (RC) existing buildings, such as seismic and energy performances, providing an eco-friendly alternative to steel external bracing systems. Cross-laminated timber (CLT) walls are provided perpendicularly to the external façades as strengthening elements while interposed CLT slabs are foreseen at each floor level to host new architectural units together with a new envelope. While the connections to the foundations and to the existing RC frames are provided respectively with steel brackets and axial-connectors distributed along the height of the building, a post-tensioned connection, between CLT panels (PT-CLT connection), is implemented in the system to guarantee resistance to horizontal actions acting parallel to existing façades with consequent structural independence and architectural freedom. A numerical model is developed with finite element software characterizing each type of connector for linear and non-linear analyses. Modal analyses with response spectrum are performed to verify structural elements and connectors, while pushover analyses with target displacement checks are performed to assess the obtained seismic improvement. Finally, the preassembled architectural components that allow to renovate the envelope and the provided assembly procedure are revealed.

Seismic Damage Assessment of Reinforced Concrete Grain Silos

This paper deals with seismic performance and damage assessment of concrete grain silos. An existing large silo is taken as a case study to conduct the numerical analyses. A global damage index based on target displacement is proposed to quantify numerically different damage states of the structure. To this aim, the classical N2 method is extended to adaptive multimodal to evaluate seismic performance of the structure for increasing pic ground acceleration levels with taking into account degradation of stiffness and modification of modal characteristics. The seismic capacity of the silo is evaluated, as an averaged curve, by conducting pushover and several incremental dynamic analyses using artificial and recorded accelerograms. The seismic demand is derived from the design spectrum of the Algerian seismic code (RPA 2003). The target displacement is determined by taking into account both the participation of the dominant modes, and the degradation of the structure’s modal characteristics. The nonlinear behavior of the structure’s walls is modeled by using nonlinear multilayered shell elements. The effect of the stored granular material is included through distributed equivalent masses. It is found that when the structure modal characteristics are updated as its stiffness is degraded, the target displacement is correctly computed. Whereas, it wrongly grows indefinitely, with increasing PGA, when constant modal characteristics of the intact structure are assumed, as usually done. The proposed global damage index is compared to three existing reliable indices. It better reflects the different damage states of studied silo.

Sensorimotor serial dependencies in head movements

On average, we redirect our gaze with a frequency at about 3 Hz. In real life, gaze shifts consist of eye and head movements. Much research has focused on how the accuracy of eye movements is monitored and calibrated. By contrast, little is known about how head movements remain accurate. I wondered whether serial dependencies between artificially induced errors in head movement targeting and the immediately following head movement might recalibrate movement accuracy. I also asked whether head movement targeting errors would influence visual localization. To this end, participants wore a head mounted display and performed head movements to targets, which were displaced as soon as the start of the head movement was detected. I found that target displacements influenced head movement amplitudes in the same trial, indicating that participants could adjust their movement online to reach the new target location. However, I also found serial dependencies between the target displacement in trial n-1 and head movements amplitudes in the following trial n. I did not find serial dependencies between target displacements and visuomotor localization. The results reveal that serial dependencies recalibrate head movement accuracy.

Position and force self-sensing piezoelectric valve with hysteresis compensation

This paper presents an approach for self-sensing piezoelectric valves. Both displacement and actuation force of piezoelectric valve can be simultaneously estimated from measurements of the charge and driving voltage. Only simple calibration is required before engineering application. The charge is obtained by software integration of the piezoelectric current sampled by DAQ card, which has the advantage of compensating leakage current by pre-estimating the leakage resistance. A PID controller is used to track the displacement, and a feedfoward compensation using Prandtl–Ishlinskii model is taken to compensate the piezoelectric hysteresis. The experimental results show that the controller can track target displacement within 2.03% of error, track force within 1.80% of error, and the maximum hysteresis of actuator is compensated from 27% to 3.75%.

Model predictive control based on time-varying efficiency for hydraulic hub-motor driving vehicle

A model predictive feedback control strategy based on time-varying efficiency is investigated and applied to a hydraulic hub-motor auxiliary system (HHMAS) in this paper. Adding HHMAS to a traditional heavy commercial vehicle can improve fuel economy and traction performance on roads with low adhesion coefficients. However, the hydraulic drive system experiences serious disturbance imposed by time-varying parameters and external conditions. Model predictive feedback control based on time-varying efficiency offers a solution for HHMAS to cope with the disadvantage of the hydraulic drive system and improve the environmental adaptability of the vehicle controller. In this study, the control law of hydraulic variable pump (HVP) target displacement is established based on temperature compensation in consideration of the influence of multiple factors on pump target displacement. For coordinated power distribution of HHMAS, the minimum wheel speed difference and the reduction in system impact are regarded as optimal control targets in adjusting the engine torque and HVP displacement and designing the model predictive controller. Simulation results show that the proposed model predictive control method can reduce the speed difference between front and rear wheels by up to 64% and can achieve the wheel speed following effect faster than the traditional proportional-integral-derivative algorithm. Given that the control parameters do not need to be calibrated in the proposed method, the calibration time is saved, and the actual development process of the hydraulic hub-motor driving vehicle is remarkably improved.

Phonetic Variation in Tone and Intonation Systems

This chapter reviews commonly recurring tendencies in the phonetic realization of tones, both in intonation and in lexical tone systems. It discusses local interactions between tonal targets, such as tonal coarticulation, dissimilatory H-raising, and rightward target displacement. Non-coarticulatory patterns include globally oriented patterns such as declination, look-ahead upstep, and final lowering as well as interactions between tone and the segmental skeleton, such as segmental anchoring, timing adjustments based on syllable structure or segmental features, and patterns of duration-driven truncation and compression of tone melodies. The chapter also considers morphosyntactically, pragmatically, and metalinguistically conditioned hyperarticulation effects arising from prominence or the Lombard effect. Lastly, it discusses issues relating to contour shape, such as the convexity or concavity of f0 movements, plateau versus sharp peak shapes for f0 maxima, and the propensity for L tones to be accompanied by a falling or dipping f0.

EVALUASI STRUKTUR GEDUNG DUAL SYSTEM DENGAN DINDING GESER BERSAYAP C MENGGUNAKAN PUSHOVER ANALYSIS

ABSTRACTAlthough elastic analysis gives a good indication of the elastic capacity and behavior of a building, but the elastic method can’t predict when the first yield will occur, and the failure mechanism and account for redistribution of member forces when the plastic hinges progressively formed. The use of inelastic procedure for evaluation is an attempt made by engineer in the past days to better understand how the structure will behave when subjected to strong earthquake, assuming the elastic capacity of the structure will be exceeded. In this research the pushover analysis was done using the modelling criteria of FEMA 356. The modeling of C-flanged shear was done using line element with the equivalent strength and stiffness properties. Target displacement was calculated using the displacement coefficient method of FEMA 356. Based on the analysis the triangular load pattern resulted in larger target displacement than the uniform load. But the uniform load pattern gives larger seismic response than the triangular load pattern. The uniform load pattern resulted in Life Safety performance level, while the triangular load pattern resulted in Immediate Occupancy, based on the two load patterns used the structure resulted in Life Safety performance level.ABSTRAKWalaupun analisis elastik memberikan indikasi yang baik mengenai kapasitas dan perilaku elastik dari suatu gedung, tetapi metode elastik tidak dapat memperkirakan kapan pelelehan pertama terjadi, serta mekanisme kegagalan apa yang mungkin terjadi pada bangunan tersebut, dan memperkirakan redistribusi dari gaya- gaya dalam ketika pembentukan sendi plastis secara progresif terjadi. Fungsi dari analisis inelastik, sebagai prosedur untuk mengevaluasi bangunan, yang merupakan usaha dari insinyur-insinyur terdahulu memahami bagaimana struktur akan berperilaku apabila dikenai gempa kuat, dimana diasumsikan bahwa kapasitas elastik gedung telah terlampaui. Dalam penelitian ini dilakukan pushover analysis menggunakan kriteria pemodelan berdasarkan FEMA 356. Pemodelan dari dinding geser bersayap C dilakukan menggunakan line element dengan kekuatan dan kekakuan yang ekivalen. Target perpindahan dianalisis menggunakan metode coefficient of displacement dari FEMA 356. Berdasarkan analisis yang dilakukan didapat bahwa pembebanan segitiga lebih besar dibandingkan pembebanan merata. Namun, respons seismik yang didapat akibat beban merata, lebih besar dibandingkan beban segitiga. Pembebanan merata menghasilkan tingkatan kinerja Life Safety, sedangkan pembebanan segitiga menghasilkan tingkatan kinerja Immadiate Occupancy, berdasarkan kedua pembebanan tersebut didapat kinerja dari struktur tersebut adalah Life Safety.