
مرتضی
اسماعیلی
author
شهرام
وهدانی
author
اسدالله
نورزاد
author
text
article
2005
per
Two dimensional harmonic response of lined circular tunnel in elastic full space mediuni against plane PSV waves is investigated .The solution uses hybrid direct boundary element method and finite element method for soil and lining, respectively. In the proposed ring element used in the modelling of lining, radial and tangential deformations are defined using Fourier series expansion. Therefore the direct unknowns of problem are introduced as coefficients of these series. Numerical results include the nondimensional shear and hoop stresses in lining as well as its interface with surrounding soil for various material properties.
University College of Engineering
دانشکده فنی
08031026
38
v.
6
no.
2005
https://jfe.ut.ac.ir/article_10218_cc3d7e3e84313547547ed61edeccd222.pdf

مهدی
خراسانچی
author
محرم
دولتشاهی
author
خسرو
برگی
author
text
article
2005
per
Based on boundary element method, a time domain solution for 3D diffraction is developed to study nonlinear interaction of ocean waves and rigid arbitrary shape structures. Solution in time is obtained from integral equation based on Green’s theorem. Free surface boundary conditions are expanded and combined to change moving boundary to constant one in time. Consequently, solving simultaneous equations, resulting from discrete sizing integral equation, is required once instead of at each time step, significantly inducing time increase. The solution is separated to known incident potential and unknown scattered one, developed in time and place and should be determined. Based on these theoretical developments, software entitled “DIFFRACTION” is produced and used in
assessing waves diffraction around arbitrary shape obstacles. The force and freesurface elevation for different cases are presented. Despite less elements and more convenient computations, surface piercing circular cylinder results are in good agreement with previous studies.
University College of Engineering
دانشکده فنی
08031026
38
v.
6
no.
2005
https://jfe.ut.ac.ir/article_10219_46caecbfea5bc38177a694dfecf7d62f.pdf

علیرضا آزموده
اردلان
author
مرضیه
جعفری
author
text
article
2005
per
A thorough study on the possibility of using TopexPoseidon satellite altimetry data for DTM generation over the land area has been conducted.
The geographical region of Iran has been selected as the test region. The study proves that repeated observations of TopexPoseidon satellite are a valuable source for increasing the precision and resolution of existing DTM’s. The theoretical details and the results of the case study will be presented
University College of Engineering
دانشکده فنی
08031026
38
v.
6
no.
2005
https://jfe.ut.ac.ir/article_10220_6023650169c64202e1a832d43f7be2e7.pdf

جعفر امیری
پریان
author
علی
عزیزی
author
text
article
2005
per
University College of Engineering
دانشکده فنی
08031026
38
v.
6
no.
2005
https://jfe.ut.ac.ir/article_10221_0acd0ac2984ae05c0d9b3970d2b108c8.pdf

اشرف السادات
قریشی
author
علی
عزیزی
author
text
article
2005
per
Multi Quadric (MQ) interpolation function is used as a postprocessing tool for the refinement of the object coordinates of the tie points obtained by the aerial triangulation (AT) technique. To apply the MQ function, initially a low order polynomial AT is applied to a photogrammetric block consisting of 4 strips and 77 photographs. The trend of the residual vector errors of the ground control points was then modeled by the MQ function. The calculated MQ coefficients were subsequently utilized to refine the ground coordinates for all tie points of the block.
The accuracy achieved by the MQ approach is compared with the standard polynomial, independent model and bundle adjustment AT techniques. The evaluated accuracy is based on the uniformly distributed checkpoints whose coordinates were determined by differential GPS receivers. The test results indicate that MQ function gives a marginal improvement of +0.2; +0.1 and +0.2 meter RMSE for the X, Y and Z coordinates of the check points respectively as compared with the polynomial AT method. However, comparing the accuracy figures with the standard independent model and bundle adjustment, noticeable improvements were not observed.
Furthermore, the MQ potential for the elimination of the residual systematic errors for tie points due to imperfect interior orientation parameters was also investigated by introducing defective interior orientation parameters during tie data capture stage. The MQ function was then applied again as a post processor for removing the systematic trend. The results show an overall improvement of + 0.80, +1.08 and +2.90 meter RMSE for the X, Y and Z coordinates of the tie points respectively. It could be concluded that the MQ interpolation function is an effective trend removal technique if camera interior orientation parameters are not known with the required accuracy. Test results also indicate that the MQ is superior to the polynomial interpolation functions as far as systematic trend removal in aerial triangulation is concerned.
University College of Engineering
دانشکده فنی
08031026
38
v.
6
no.
2005
https://jfe.ut.ac.ir/article_10222_43738a46b4f4377c5803d96d2a829243.pdf

محمد رضا جلیلی قاضی
زاده
author
امیر رضا
زراتی
author
text
article
2005
per
In the present paper application of a oneneedle and a doubleneedle electrical probe with developed specifications is introduced for measurement in airwater flows. The new oneneedle probe has the capability of measuring air concentration and bubble count with very high sampling frequency. Another advantage of this probe is real time measurement and online presentation of results. More than 30 sets of tests were carried out in airwater flows to calibrate the probe and to determine the circuit threshold level. To measure the velocity of air water mixture a doubleneedle electrical probe is employed. The specifications of the double needle probe are similar to the oneneedle probe with addition of one needle to make it capable of measuring flow velocity. To ensure the performance of the douNeneedle probe, its measurements were compared with a pilot tube. This comparison showed that the maximum difference in measurements was less than 4%.
University College of Engineering
دانشکده فنی
08031026
38
v.
6
no.
2005
https://jfe.ut.ac.ir/article_10223_b25de1f757656d93f330b2a4ae66294d.pdf

مهرداد
حجازی
author
رسول میر
قادری
author
text
article
2005
per
Iranian traditional domes are of the most notable samples of traditional construction in Iran during thousands of years, many of which still standing on seismic parts of the country for many centuries.
Structurally, Iranian domes can be categorised into single, double and tripleshell domes. Singleshell domes are the earliest type of domes. The singleshell is the main load bearing part. Doubleshell domes consist of two shells, and they are divided into continuous and discontinuous types. In continuous doubleshell domes the distance between the two shells is small and shells are connected by brick connectors. In discontinuous doubleshell domes there is a considerable distance between the two shells. For structural stability of some domes meridional walls or stiffeners are built in the space between the two shells. There are also a few domes with three shells.
In this paper, structural systems of a number of Iranian historical domes made of masonry materials will be discussed and their structural strength and stability due to dynamic effects of earthquake will be presented. The document will also explain the structural role of meridional stiffeners in doubleshell domes.
University College of Engineering
دانشکده فنی
08031026
38
v.
6
no.
2005
https://jfe.ut.ac.ir/article_10224_5bbbdc88d7d69474d6eb486ccae7d4d0.pdf

محمد رضایی
پژند
author
مهدی
سالیانی
author
text
article
2005
per
Some methods are discussed for damage assessment of trusses. The authors developed one of these methods for suitable use of displacement and strain data. Analytical or experimental data can be used in this analysis. Also, the proposed method is able to use substructure. When the damage occurred in a part of truss, or a specific part of structure is not available, or lack of measurement devices, one can utilize substructures analysis. The damage of several plane trusses are estimated by author’s computer program and the results are given in the paper.
University College of Engineering
دانشکده فنی
08031026
38
v.
6
no.
2005
https://jfe.ut.ac.ir/article_10225_366666109f378fed32a16ab1d5e59ea3.pdf

عباس قلندر
زاده
author
رامین
معتمد
author
text
article
2005
per
In order to seismic microzonation of Urmai city microtremors were measured at 220 stations during a comprehensive study. Measurements were conducted with two different approaches, those are withreference and nonreference methods. Different aspects of site effect problem were studied by using the recorded data. Two so called Hs/Hr and H/V methods were examined in this study. Results showed that Hs/Hr method failed to give clear resonance peak at predominant frequency of the site when the distance between the site and reference station was more than 2500 meter. Whereas FL’V method successfully indicated the predominant frequency at any distances. The distance of 2500 meter is introduced as the threshold distance for validity of Hs/Hr method.
Suitability of microtremor method for detection of topography effect was also examined. For this purpose the measured data at 5 stations located at Shahrake Electronic hill, southeast of Urmia city were utilized. Two horizontal components of measured microtremors were compared to the vertical one. Results showed that at the stations located at the top portion of the hill there was significant amplification whereas for the stations located at the hill foot the amplification was negligible. This means the microtremor method could successfully distinguish the topography effect. Moreover, the results showed that for selection of a suitable rock station the microtremors recorded on a rock outcropping should be free of any topography effect; otherwise Hs/Hr method could not show reliable results.
University College of Engineering
دانشکده فنی
08031026
38
v.
6
no.
2005
https://jfe.ut.ac.ir/article_10226_0797fe988a2d97a6bdf4b6500d7db5ac.pdf

بهروز
گتمیری
author
احسان
جباری
author
text
article
2005
per
Numerical modeling has been largely developed in soil mechanics behavior by different methods. Among them, the development of the boundary element method, which is the most suitable one for domains with infinite boundary conditions like soils media, has been restricted by the necessity of deriving the Green’s functions of the governing differential equations. Indeed, attempting to solve the threedimensional boundary value problems for unsaturated soils leads one to search for the associated Green’s functions of the governing differential equations.
In this paper the governing differential equations of the phenomena are presented which consist of three main groups of equations: 1 equilibrium and constitutive equations of soil’s solid skeleton, 2 conservation and transfer equations for air phase and 3 conservation and transfer equations for moisture phase.
The associated Green’s functions have been manipulated with a few assumptions to first linearize the completely nonlinear governing differential equations and next to make possible deriving the results, mathematically. After applying the Laplace transform to eliminate the time variable, Green’s functions of the governing differential equations have been derived using the straightforward Kupeadze’ s method. Then using the inverse Laplace transforms, the completely closedform Green’s functions have been derived in the time domain.
Finally, for verification of the results it has been demonstrated that when the conditions approach to the poroelastostatic case, the Green’s functions approach to the corresponding poroelastostatic Green’s functions as well. As no analytical solutions are available in the literature for the mentioned Green’s functions, it seems to be a new experience to introduce a set of fundamental solutions for the unsaturated case for the first time.
University College of Engineering
دانشکده فنی
08031026
38
v.
6
no.
2005
https://jfe.ut.ac.ir/article_10227_d814605617439cb605c01913f97c1055.pdf

نویدگنجیان
author
اورنگ
فرزانه
author
فرج الله
عسکری
author
text
article
2005
per
Presented is a rigorous solution for the threedimensional stability analysis of convex slopes with corners in plan view. The method is based on the upperbound theorem of limit analysis approach. A rigidblock translational
collapse mechanism is considered, with energy dissipation taking place along planar velocity discontinuities. This mechanism is optimized to obtain the minimum factor of safety for stability of the corners. The algorithm can also be used to determine the ultimate limit load of a foundation located on a corner. Based on comparisons with known solutions, the method was generally found to be accurate in predicting the stability of such slopes. The numerical results indicate that the unloaded corners are more stable than the straight slopes. Dimensionless diagrams for various corner angles are also presented.
University College of Engineering
دانشکده فنی
08031026
38
v.
6
no.
2005
https://jfe.ut.ac.ir/article_10228_9633b19d5cac9b85ae5fe7ce1fe8386b.pdf

علیرضا آزموده
اردلان
author
مرضیه
باعث
author
text
article
2005
per
In this paper we are presenting a methodology, which can remove the effect of ionospheric refraction (ionospheric error) on the coordinates derived by single frequency GPS receivers up to 85 percent at a radius of 1400 km around the computational point. The method is based on the GPS observations being made at the permanent GPS stations, according to the following procedure: (i) The realtime GPS observations being made at the permanent GPS station is compared, epoch wise, with precisely known coordinates of the permanent station and the time series of coordinate variations in x, y, and z component {?xi,?x,?z} is derived. (ii) Fast Fourier technique is applied in order to transfer each components of the variations vector {?x,?y,?z} from the time domain into frequency domain. (iii) The plot of the resulted periodogram provided us with the frequency vector {fx,fy,fz} of the ionospheric refraction
(ionospheric error) with nearly 24 hour period. (iv) Having derived the frequency vector {fx,fy,fz} of the ionospheric refraction, a sinusoidal models of the form
?xi= ?i0 + ?i1 cos(wit — ?i) (where w = 2?f) is fitted to the coordinate differences {?x,?y,?z} via least squares technique. As a case study, 25 day observations of the permanent GPS station of Tehran National Cartographic Center (NCC) is used.
University College of Engineering
دانشکده فنی
08031026
38
v.
6
no.
2005
https://jfe.ut.ac.ir/article_10229_8db9d1aa2c04ed22218ca9f0a9cc8d38.pdf

عبدالرضا
صفری
author
علیرضا ازموده
اردلان
author
text
article
2005
per
In this paper AbelPoisson boundary value problem with boundary data of the type gravity intensity (from gravimetry) and sea surface height (from satellite altimetry) as a solution to geoid computation problem is presented. This method besides its high accuracy from its theoretical point of view, addresses the problem of highaccuracy geoid computations in the coastal areas. The highlights of the method are:
 Application of ellipsoidal harmonic expansion up to degree/order 360 / 360 and ellipsoidal centrifugal field for the removal of the effect of global gravity and isostasy field from the gravity intensity observations at the surface of the earth.
 Application of ellipsoidal Newton integral on the multicylindrical equal area map projection surface for the removal of the residual mass effects within a radius of 55 km around the computational point from the gravity intensity and astronomical observations at the surface of the earth.
 Application of ellipsoidal harmonic expansion up to degree/order 360 / 360 and ellipsoidal centrifugal field for the removal of the effect of global gravity and isostasy on the geoidal undulations from the geoidal undulations derived from satellite altimetry.
 Application of ellipsoidal Newton integral on the multicylindrical equal area map projection surface for the removal of the effect of the water masses outside the reference ellipsoid within a radius of 55 km around the
computational point from the geoidal undulations derived from satellite altimetry.
 Least squares solution of the observation equations of the incremental quantities derived from aforementioned stages in order to obtain the incremental gravity potential at the surface of reference ellipsoid.
 Restore of the removed effects at the application points on the surface of reference ellipsoid.
 Application of ellipsoidal Bruns formula for converting the potential values on the surface of the reference ellipsoid into the geoidal heights with respect to the reference ellipsoid.
As the case study, computation of the high resolution geoid of Iran based on gravity intensity and sea surface height from TopexPosseidon satellite altimetry data is presented.
University College of Engineering
دانشکده فنی
08031026
38
v.
6
no.
2005
https://jfe.ut.ac.ir/article_10230_2edd489c6cba87ed6285af0e8f21ff30.pdf

علیرضا ازموده
اردلان
author
روح الله
کریمی
author
text
article
2005
per
The possibility of modeling gravity field of the Earth along the leveling lines using the gravity observations at the leveling benchmarks has been studied. As the case study, gravity observations along the first orderleveling network of Iran has been considered. The mathematical models that have been developed for this purpose are
polynomials of degree 4 and degree 8. The efficiency of the aforementioned models has been compared with the ellipsoidal harmonic expansion to degree and order 20, 180, 360 and the SomiglianaPizzeti gravity field. The test computations have proven that a polynomial model of degree 4 can be considered as the best choice for the gravity field modeling along the leveling lines. Based on the case study of gravity field modeling along the leveling lines of Iran, the polynomial model of degree 4 can provide 20 mGal accuracy which is quite enough to provide the accuracy level of the gravity data needed for the precise leveling based on the current demands. Therefore, by applying such a model the need for the gravity observations along the leveling lines will be reduced and as such great reduction in the expense of the precise leveling observations will be achieved
University College of Engineering
دانشکده فنی
08031026
38
v.
6
no.
2005
https://jfe.ut.ac.ir/article_10231_dc5022394e27732e6a4d1fa624c35c69.pdf

فرهاد صمد
زادگان
author
علی
عزیزی
author
محمد
سرپولکی
author
text
article
2005
per
This research work is concerned with the digital surface reconstruction of Cheshmeh Au historical site using the method of digital close range photogrammetry. Regarding the size of the site and other photogram metric factors such as film resolution, camera frame size, etc. four imaging stations were considered. Hasselblad non metric camera was installed on each predetermined station successively and four %80 overlapping images were taken to cover the entire area of the site. These images were then scanned with Intergraph scanner with a resolution of 14 micron pixel size. Nonlinear image distortions, which were mainly due to the camera low geometric stability, were then modeled using the Multi Quadric (MQ) interpolation function. The MQ coefficients were determined using a dense pattern of
control points. The object space coordinates of the control points were measured by total station. The statistical tests indicated an accuracy level of ±36 micrometer in image space for the checkpoints. The MQ coefficients were then used in the later stage to resample the original images and hence effectively the generated resampled output data were nearly free from distortions. These images were then fed into the ParadEyes DSP system to generate a three dimensional photogram metric model. The X, Y and Z coordinates of the site were then extracted manually from the 3D models using the operator’s interactive capability offered by the DSP. The connectivity of the common features in the adjacent models was ensured using the stereo superimposition potentials of ParadEyes system. The geometric accuracy of the reconstructed 3D surface is estimated about ± 5 millimeter.
University College of Engineering
دانشکده فنی
08031026
38
v.
6
no.
2005
https://jfe.ut.ac.ir/article_10232_50187482b41cc937e5d0ebf8dda2c933.pdf