The Study of Optimal Design Method for Safe Monitoring in Tunnel

2011 ◽  
Vol 374-377 ◽  
pp. 2538-2542
Author(s):  
Ming Zhong Gao ◽  
Hui Ma ◽  
Xiang Chao Shi

The deformation tendency and order of magnitude for surrounding rock, expressing the state of rock mass, always change the construction schemes and treatment measures. The monitoring is the most important guarantee for safety construction and operation in civil engineering. However, due to the unsuitable monitoring sections and equipments selected, the budget remains stubbornly high. Most of business owners just carry out some of them or even give up the monitoring. This brings enormous hidden trouble to construct. Based on the Doupengshan highway tunnel, the optimal design method for safety monitoring was studied by comprehensive analysis of the geological conditions, the results of numerical modeling and monitoring data. The main aim of monitoring is to obtain the most poor condition information rather than all of them. It’s best to employ different type of monitoring instruments in order to verify results each other. That is to say, the monitoring of internal force or displacement can take the place of the convergence monitoring every two sections. The new monitoring design saves the budget 20% than origin one. The research result will guide the monitoring design for similar engineering.

2021 ◽  
Vol 11 (7) ◽  
pp. 3266
Author(s):  
Insub Choi ◽  
Dongwon Kim ◽  
Junhee Kim

Under high gravity loads, steel double-beam floor systems need to be reinforced by beam-end concrete panels to reduce the material quantity since rotational constraints from the concrete panel can decrease the moment demand by inducing a negative moment at the ends of the beams. However, the optimal design process for the material quantity of steel beams requires a time-consuming iterative analysis for the entire floor system while especially keeping in consideration the rotational constraints in composite connections between the concrete panel and steel beams. This study aimed to develop an optimal design method with the LM (Length-Moment) index for the steel double-beam floor system to minimize material quantity without the iterative design process. The LM index is an indicator that can select a minimum cross-section of the steel beams in consideration of the flexural strength by lateral-torsional buckling. To verify the proposed design method, the material quantities between the proposed and code-based design methods were compared at various gravity loads. The proposed design method successfully optimized the material quantity of the steel double-beam floor systems without the iterative analysis by simply choosing the LM index of the steel beams that can minimize objective function while satisfying the safety-related constraint conditions. In particular, under the high gravity loads, the proposed design method was superb at providing a quantity-optimized design option. Thus, the proposed optimal design method can be an alternative for designing the steel double-beam floor system.


2021 ◽  
Author(s):  
Nalika Ulapane ◽  
Karthick Thiyagarajan ◽  
sarath kodagoda ◽  
Linh Nguyen

<div>Identification of static nonlinear elements (i.e., nonlinear elements whose outputs depend only on the present value of inputs) is crucial for the success of system identification tasks. Identification of static nonlinear elements though can pose several challenges. Two of the main challenges are: (1) mathematical models describing the elements being unknown and thus requiring black-box identification; and (2) collection of sufficiently informative measurements. With the aim of addressing the two challenges, we propose in this paper a method of predetermining informative measurement points offline (i.e., prior to conducting experiments or seeing any measured data), and using those measurements for online model calibration. Since we deal with an unknown model structure scenario, a high order polynomial model is assumed. Over fit and under fit avoidance are achieved via checking model convergence via an iterative means. Model dependent information maximization is done via a D-optimal design of experiments strategy. Due to experiments being designed offline and being designed prior to conducting measurements, this method eases off the computation burden at the point of conducting measurements. The need for in-the-loop information maximization while conducting measurements is avoided. We conclude by comparing the proposed D-optimal design method with a method of in-the-loop information maximization and point out the pros and cons. The method is demonstrated for the single-input-single-output (SISO) static nonlinear element case. The method can be extended to MISO systems as well.</div>


2008 ◽  
Vol 75 (4) ◽  
Author(s):  
Chuanxiang Zheng ◽  
Shaohui Lei

Stress analysis of flat steel ribbon wound pressure vessels (FSRWPVs) is very difficult because they have a special discrete structure and complex pretensions exit in the flat steel ribbons, which are wound around the inner shell layer by layer. An analytical multilayered model for stress analysis is presented in this paper, which involves the effect of prestress in every flat steel ribbon layer as well as in the inner shell. Based on this model, an optimal design method for FSRWPV is suggested, which can assure a reasonable stress level and distribution along the wall thickness during the operation. A practical example of a large FSRWPV is finally given for illustration.


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