18
1735-0522
756
Structure-Earthquake
Comparative study of endurance time and time history methods in seismic analysis of high arch dams
Hariri Ardebili
Mohammad amin
^{
b
}
Mirzabozorg
Hasan
^{
c
}
Kianoush
Reza
^{
d
}
^{
b
}University of Colorado at Boulder
^{
c
}K. N. Toosi University of Technology
^{
d
}Ryerson University
1
6
2014
12
2
121
138
13
08
2012
28
10
2013
In the present study, the application of Endurance Time Analysis (ETA) method is investigated on seismic analysis of a high
arch dam. In this method the coupled system is excited using the predesigned intensifying acceleration functions instead of the
real ground motions. Finite element model of an arch dam considering the dam-rock-water interaction effects was developed
in which the concrete and rock were assumed to have linear elastic behavior. The effect of the large displacement in dam body
was considered in numerical model using co-rotational approach. The coupled system was analyzed by conventional Time
History Analysis (THA) method in various seismic performance levels and the results were compared with those obtained from
ETA at the equivalent target time. It was found that ETA method provides the close results to THA with acceptable accuracy
while it reduces the total time of the analyses considerably.
769
Structure-Earthquake
AN INVESTIGATION ON SEISMIC DESIGN INDICATORS OF RC COLUMNS USING FINITE ELEMENT ANALYSES
Arslan
Guray
^{
e
}
HACISALIHOGLU
Melih
^{
f
}
BALCI
Muzaffer
^{
g
}
BOREKCI
Muzaffer
^{
h
}
^{
e
}Yildiz Technical University
^{
f
}Yildiz Technical University
^{
g
}Yildiz Technical University
^{
h
}Yildiz Technical University
1
6
2014
12
2
139
145
18
09
2012
19
11
2013
The main cause of structural damage in buildings subjected to seismic actions is lateral drift. In almost all reinforced concrete (RC) structures, whether designed with walls or frames, it is likely to be the code drift limits that control the design drift. The design drift limits and their contribution to damage may be represented indirectly through the material strain limits. The aim of this study is to investigate the seismic design indicators of RC columns using finite element analyses (FEA). The results of FEA have been compared with the results of experimental studies selected from literature. It is observed that the lateral load-deflection curves of analyzed columns are in agreement with the experimental results. Based on these lateral load-deflection curves, the drift limits and the material strain limits, given by the codes as performance indicator, are compared. It is observed that the material strain limits are non-conservative as performance indicator of RC columns, compared to the drift limits.
795
Structure-Earthquake
The Effect of Foundation Uplift on Elastic Response of Soil-Structure Systems
Jafarieh
Amir Hossein
^{
i
}
Ghannad
Mohammad Ali
^{
j
}
^{
i
}Sharif University of Technology
^{
j
}Sharif University of Technology
1
6
2014
12
2
146
157
12
11
2012
28
10
2013
It is well-known that the behavior of soil-structure systems can be well described using a limited number of non-dimensional parameters. This is the outcome of researches based on the premise that the foundation is bonded to the ground. Here, it is shown the concept can be extended to systems with foundation uplift. A set of non-dimensional parameters are introduced which controls the main features of uplifting systems. The effect of foundation uplift on response of soil-structure systems are investigated parametrically through time history analysis for a wide range of systems subjected to ground motions recorded on different soil types. In particular, the effects of uplift on displacement ratio, defined as the ratio of maximum displacement of the uplifting system to that of the elastic system without uplifting and drift ratio, defined as the ratio of maximum drift of the structure as a part of uplifting soil-structure system to that of the elastic system without uplifting, are investigated. It is observed that in general foundation uplift reduces the drift response of structures, which in turn, results in lower base shear. The reduction reaches about 35 percent for slender structures located on relatively soft soils subjected to strong ground motions. Simplified expressions are suggested to estimate this reduction in the base shear.
788
Structure-Earthquake
Improved Seismic Design of Structural Frames by Optimization of Equivalent Lateral Load Pattern
Shahrouzi
Mohsen
^{
k
}
Rahemi
Amir Abbas
^{
l
}
^{
k
}Kharazmi University
^{
l
}Kharazmi University
1
6
2014
12
2
158
169
29
10
2012
13
01
2014
Well-known seismic design codes have offered an alternative equivalent static procedure for practical purposes instead of verifying design trials with complicated step-y-step dynamic analyses. Such a pattern of base-shear distribution over the building height will enforce its special stiffness and strength distribution which is not necessarily best suited for seismic design. The present study, utilizes a hybrid optimization procedure to seek for the best stiffness distribution in moment-resistant building frames. Both continuous loading pattern and discrete sizing variables are treated as optimization design variables. The continuous part is sampled by Harmony Search algorithm while a variant of Ant Colony Optimization is utilized for the discrete part. Further search intensification is provided by Branch and Bound technique. In order to verify the design candidates, static, modal and time-history analyses are applied regarding the code-specific design spectra. Treating a number of building moment-frame examples, such a hyper optimization resulted in new lateral loading patterns different from that used in common code practice. It was verified that designing the moment frames due to the proposed loading pattern can result in more uniform story drifts. In addition, locations of the first failure of columns were transmitted to the upper/less-critical stories of the frame. This achievement is important to avoid progressive collapse under earthquake excitation.
743
Structure- Concrete
Static and dynamic modulus of elasticity of structural lightweight and modified density concrete with and without nanosilica – characterization and normalization
Bogas
Jose
^{
m
}
Gomes
Augusto
^{
n
}
^{
m
}IST-Technical Univ. of Lisbon
^{
n
}IST-Technical Univ. of Lisbon
1
6
2014
12
2
170
180
11
07
2012
04
01
2014
This paper aims to characterize the elastic modulus of structural modified normal density (MND) and lightweight aggregate concrete (LWAC) produced with different types of expanded clay lightweight aggregates (LWA). A comprehensive experimental study was carried out involving different concrete strengths ranging from 30 to 70 MPa and density classes D1.6 to D2.0. The influence of several factors on the LWAC elastic modulus, such as the cement content, initial wetting conditions, type and volume of coarse LWA and the partial replacement of normal weight coarse and fine aggregates by LWA are analyzed. The strength and deformability of LWAC seems to be little affected by the addition of high reactive nanosilica. Reasonable correlations are found between the elastic modulus and the compressive strength or concrete density. The obtained LWAC elastic moduli are compared with those reported in the literature and those estimated from the main normative documents. In general, codes underestimate the LWAC modulus of elasticity by less than 20%. However, the MND modulus of elasticity can be greatly underestimated. In addition, the prediction of LWAC elastic modulus by means of non-destructive ultrasonic tests is studied. Dynamic elasticity modulus and ultrasonic pulse velocity results are reported and high correlated relationships, over 0.95, with the static modulus are established.
738
Construction Management
Inspection and diagnosis system for rendered walls
Sá
Gonçalo
^{
o
}
Sá
João
^{
p
}
de Brito
Jorge
^{
}
Amaro
B.
^{
}
^{
o
}IST - Technical University of Lisbon
^{
p
}IST - Technical University of Lisbon
^{
}IST - Technical University of Lisbon
^{
}IST - Technical University of Lisbon
1
6
2014
12
2
181
192
26
06
2012
21
01
2014
This paper presents an inspection and diagnosis system customized for rendered walls, both interior and external. It classifies all anomalies capable of affecting renderings and most of the likeliest corresponding causes and is supplemented by anomaly-cause and inter-anomaly correlation matrices. In addition, the diagnosis, repair and maintenance techniques suitable for these anomalies are classified. Examples of the files that contain the exhaustive characterization of the anomalies and diagnosis, repair and maintenance techniques are also presented.
The system is the result of an intense literature review, which allowed collecting and organizing the information available on pathology of renders. Next it was validated by mathematical manipulation of the data collected from standard inspections of 55 buildings, in which 150 renderings (100 exterior and 50 interior) were examined.
The system proposed may be included in a proactive maintenance strategy, since it is robust, reliable and has been statistically validated. The systematic structure of this system is innovative and can help the inspector by making his/her work more objective and standardizing procedures.
Anomalies in wall renderings may be prevented/minimized if buildings are properly managed by developing and implementing proactive maintenance plans that cover the following areas: technology (adequate maintenance and repair solutions, including the selection of materials and execution techniques), economy (minimizing running costs) and functionality (appropriate use).
980
Structure-Steel
Damage detection in skeletal structures based on charged system search optimization using incomplete modal data
Kaveh
A.
^{
}
Maniat
M.
^{
}
^{
}Professor
^{
}MSc student
1
6
2014
12
2
193
200
23
08
2013
20
05
2014
It is well known that damaged structural members may alter the behaviour of the structures considerably. Careful observation of these changes has often been viewed as a means to identify and assess the location and severity of damages in structures. Among the responses of a structure, natural frequencies and natural modes are both relatively easy to obtain and independent from external excitation, and therefore, can be used as a measure of the structural behaviour before and after an extreme event which might have led to damage in the structure. This paper applies Charged System Search algorithm to the problem of damage detection using vibration data. The objective is to identify the location and extent of multi-damage in a structure. Both natural frequencies and mode shapes are used to form the required objective function. To moderate the effect of noise on measured data, a penalty approach is applied. Varity of numerical examples including beams, frames and trusses are examined. The results show that the present methodology can reliably identify damage scenarios using noisy measurements and incomplete data.
761
Design
RELATIVE PERFORMANCES OF COMPOSITE CONOIDAL SHELL ROOFS WITH PARAMETRIC VARIATIONS IN TERMS OF STATIC, FREE AND FORCED VIBRATION BEHAVIOR
Bakshi
Kaustav
^{
}
Chakravorty
Dipankar
^{
}
^{
}Jadavpur University
^{
}Jadavpur University
1
6
2014
12
2
201
213
30
08
2012
19
10
2013
A review of literature reveals that although singly curved conical shells applicable in many fields of mechanical engineering have been studied by many researchers but doubly curved conoidal shells which are very popular as civil engineering roofing units have not received due attention. Hence relative performances of composite conoidal shells in terms of displacements and stress resultants are studied in this paper under static and dynamic loadings. Free vibration frequencies are also reported. A curved quadratic isoparametric eight noded element is used to model the shell surface. Clamped and simply supported boundary conditions are considered. Results obtained from the present study are compared with established ones to check the correctness of the present approach. A number of additional problems of composite conoidal shells are solved for eight different stacking sequences of graphite-epoxy composite for each of the edge conditions. Uniformly distributed load for static bending analysis and step load of infinite duration for solution of forced vibration problem are considered. The results are interpreted from practical application standpoints and findings that are important for a designer to note, before he decides on the shell combination he will finally adopt among a number of possible options, are highlighted.
812
Design
Assessment of masonry buildings subjected to landslide by using the load path method
Palmisano
Fabrizio
^{
}
Elia
Angelo
^{
}
^{
}DICATECh, Politecnico Bari
^{
}PPV Consulting
1
6
2014
12
2
214
232
16
12
2012
11
01
2014
The increase in the computational capabilities in the last decade has allowed numerical models to be widely used in the analysis, leading to a higher complexity in structural engineering. This is why simple models are nowadays essential because they provide easy and accessible understanding of fundamental aspects of the structural response. Accordingly, this article aims at showing the utility and effectiveness of a simple method (i.e. the Load Path Method) in the interpretation of the behaviour of masonry buildings subjected to foundation settlements due to landslide. Models useful for understanding brick-mortar interface behaviour as well as the global one are reported. The global proposed approach is also validated by using Bi-directional Evolutionary Structural Optimization method.
Moreover, drawing inspiration from a case study, the article shows that the proposed approach is useful for the diagnosis of crack patterns of masonry structures subjected to landslide movements.
701
Transportation
Vehicle routing problem with multiple decision-makers for construction material transportation in a fuzzy random environment
Ma
Yanfang
^{
}
Xu
Jiuping
^{
}
^{
}Sichuan University
^{
}Sichuan University
1
6
2014
12
2
233
248
20
04
2012
02
10
2013
In this paper, a bi-level decision making model is proposed for a vehicle routing problem with multiple decision-makers (VRPMD) in a fuzzy random environment. In our model, the objective of the leader is to minimize total costs by deciding the customer sets, while the follower is trying to minimize routing costs by choosing routes for each vehicle. Demand for each item has considerable uncertainty, so customer demand is considered a fuzzy random factor in this paper. After setting up the bi-level programming model for VRPMD, a bi-level global-local-neighbor particle swarm optimization with fuzzy random simulation (bglnPSO-frs) is developed to solve the bi-level fuzzy random model. Finally, the proposed model and method are applied to construction material transportation in the Yalong River Hydropower Base in China to illustrate its effectiveness.
1123
Structure-Steel
Efficient finite element analysis using graph-theoretical force method tetrahedron elements
Kaveh
A.
^{
}
Massoudi
M.S.
^{
}
^{
}Iran University of Science and Technology
^{
}Iran University of Science and Technology
1
6
2014
12
2
249
269
19
04
2014
01
06
2014
Formation of a suitable null basis is the main problem of finite elements analysis via force method. For an optimal
analysis, the selected null basis matrices should be sparse and banded corresponding to sparse, banded and well-conditioned
flexibility matrices. In this paper, an efficient method is developed for the formation of the null bases of finite element models
(FEMs) consisting of tetrahedron elements, corresponding to highly sparse and banded flexibility matrices. This is achieved by
associating special graphs with the FEM and selecting appropriate subgraphs and forming the self-equilibrating systems
(SESs) on these subgraphs. Two examples are presented to illustrate the simplicity and effectiveness of the presented graph-algebraic method.
740
Water-Hydrology
Applying Digital Image Correlation Method to Measure Flow Field
Kuo
Jui-Chao
^{
}
Kuo
Teng-Yi
^{
}
Wu
Cheng-Han
^{
}
Tung
Shih-Heng
^{
}
Shih
MIng-Hsiang
^{
}
Sung
Wen-Pei
^{
}
Hwang
Weng-Sing
^{
}
^{
}National Cheng-Kung University
^{
}National Cheng-Kung University
^{
}National Cheng-Kung University
^{
}National University of Kaohsiung
^{
}National Chi Nan University
^{
}National Chin-Yi University of Technology
^{
}National Cheng-Kung University
1
6
2014
12
2
270
275
09
07
2012
28
12
2013
In this study digital image correlation (DIC) technique combined with a high speed video system was used to predict movement of particles in a water model. Comparing with Particle-image velocimetry (PIV) technique, it provides a low cost alternative approach to visualize flow fields and was successfully employed to predict the movement of particles in a water model at different submergence depth using gas injection. As the submergence depth increases, the number of the exposed eye is reduced accordingly. At 26.4 cm submergence depth, an exposed eye was found at 1/3 of the submergence depth, whereas two exposed eyes were observed at 1/2 depth and near the bottom wall at 24 cm submergence depth.