In urban areas, tunneling is accompanied by ground surface settlement. To reduce the risks of the operation, it is always required to have an assessment of ground surface settlement and face pressure. In the evaluation of the face pressure, there are two major sets of methods based on the ultimate limit state (ULS) (e. g. tunnel face failure), and serviceability limit state (SLS) (e. g. unacceptable settlement or heave). In a serviceability limit state, volume loss and surface settlement are used for the analysis of the face pressure. The methods developed for the analysis of SLS face pressure are based on the results of small-scale centrifuge tests or case studies with the unpressurized face. Hence, realistic face pressure cannot be evaluated with these methods. This paper summarizes the major strategies for the evaluation of face pressure in an undrained condition. The outlined methods are utilized to evaluate tunnel face pressure in the Tehran metro line 6, south extension (ML6-SE) project. Results of the analyses showed that predicted face pressures with the SLS methods are far above the required face pressure. To make realistic SLS face pressure evaluations in this project (considering a maximum allowable surface settlement of 10 mm), using ground characteristics and TBM operational parameters, a new formula was introduced with a coefficient of determination of 84%. The results of this paper can be very helpful for both the design phase of a tunneling project and the construction period to adjust the face pressure based on the requirement of the allowable surface settlement.

Flutter and limit cycle oscillations (LCO) control of a structural non-linear wing with actuator saturation is considered in this paper. For this purpose composite Nonlinear feedback (CNF) theory is used The CNF theory accounts for the effect of actuator saturation and here it can be shown, this control method can effectively suppress the flutter and LCO of a structural Nonlinear wing with constrained input. The aeroelastic model is a low aspect ratio rectangular wing in a low subsonic flow with structural Nonlinearities. The structural Nonlinearity arises from double bending in both chord-wise and span-wise directions (Von Karman plate theory). For aerodynamics modeling a full and reduced order aerodynamics model based on the modified vortex lattice method is used Results from simulations show, with this simple controller, we can effectively suppress LCO and extend flutter boundary.

This paper presents a study on the selection of engineering demand parameters (EDPs) for the definition of collapse forcode-conforming reinforced concrete buildings. The definition of collapse for buildings is not unique, as different codesand authors define it with respect to different EDPs and different values of the EDPs. Since collapse is associated with largeplastic deformations, collapse is typically defined by deformation, displacement, and eventually energy EDPs. The EDPscan be either local when they refer to a single structural element response parameter (such as element rotation with respectto the chord) or global when they refer to an overall building response parameter (such as inter-story drift or top floor displacement). The Italian buildings code NTC2008 and Eurocode 8 use the chord rotation as EDP, while FEMA 356 and otherNorth American literature use inter-story drift ratio. This study compares different definitions of EDPs and different valuesof the selected EDPs by analyzing two code-conforming benchmark buildings, one six-story and the other nine-story high, designed according to Italian code. Multiple-stripe, non-linear dynamic analyses are carried out on the two buildings modeledwith concentrated hinges. The results show that different collapse definitions lead to very different safety evaluationsand point to the need for the definition of a single EDP and a single value to make collapse analyses (and risk assessment)studies comparable.

Public infrastructure is often monitored to assess quality. Alarm thresholds indicate when actions are necessary to improve passenger convenience and operational safety. Based on safety assessments, urgent rail replacements are proposed with a new approach for physical damage threshold extraction. Railway tracks are crucial in transportation, and physical damage can greatly affect their efficiency. During regular visual inspections, inspectors can identify physical damages such as head checks or fatigue cracks. However, there are no definite thresholds to determine the severity of the damages except for rail profile deformation known as wear, which is based on references and standards. Therefore, during the survey and inspection, it is essential to establish alarm thresholds based on limit states for each case. Defects detected before the ultimate limit state can lead to a reduction in quality, which affects the convenience of travel but is not harmful to serviceability. Structure quality control methods use both qualitative and quantitative approaches to assess these cases. However, quantitative assessment reduces the probability of human errors and subjective judgments by inspectors when compared to qualitative assessment. To begin with, image processing is a quantitative tool used to detect defects on rail surfaces. However, the determination of the threshold has been neglected, leading to a lack of anticipation of rail physical damages' lifetime and cost estimation. Therefore, machine learning tools evaluate the output of image processing based on the proposed threshold, which has been expressed in this research. In order to ensure safety, contingency actions will be taken when needed based on the predetermined alarm thresholds.