Change In Cross-sectional Dimensions Research Articles

Measurement of Geometric Variations of a Railway Truss Bridge (Case Study: BH77 Railway Bridge)

Monitoring the condition of the railway track on a regular basis needs to be carried out regularly to minimize risk. One of the causes of the decrease in the strength of the bridge structure can be caused by changes in cross-sectional dimensions. The existing dimensions of the bridge structure need to be known because they will affect the steel frame profile area, where the steel frame area will affect the size or the small value of the deflection and stress of the bridge structure. The dimensions of the frame need to be seriously considered so that the stress and deflection values ??of the bridge structure remain constant. This research was conducted at the BH 77 Railway Bridge in Tegineneng, Tanjungkarang-Martapura, Lampung, which uses a type frame configuration warren truss. This location was chosen to fit the research that was also conducted by Badan Riset dan Inovasi Nasional (National Research and Innovation Agency of Indonesia). Based on the measurement of the dimensions of the bridge truss that has been carried out, the results show that there is a difference in the value of the circumference of each rod with the standard deviation for each similar profile. The biggest difference in the circumference of the truss is the profile of H beam, 113 and 115 rods with dimensions of 340×300×15×18, the initial circumference value is 1,280 mm, and after the measurement is 1,289.42 mm with a standard deviation value of 0.91 mm. while for the smallest difference, namely the H beam profile, rod 110 with dimensions of 340×310×39×21, the initial circumference value is 1,300 mm and after the measurement is 1,300.33 mm with a standard deviation value of 0.24 mm.

Stitched Transmission Line for Broadband Operations

Wearable stitched transmission lines made from stripped RG174 and textile materials are introduced for broadband operations. The stitched transmission lines which are 150 mm long consists of an inner conductor surrounded by a tubular insulating layer. For shielding purposes, the structures are stitched into a denim material with conductive threads. The performances of the stitched transmission lines with three different stitch patterns, Double Overlock, Flatlock stitch and Ric-Rac stitch were investigated and results obtained confirm that Ric-Rac stitched transmission line has fewer DC losses than the three stitched transmission lines for frequencies up to 1 𝐺𝐻𝑧. However, beyond that up to 2.4 𝐺𝐻𝑧 and above, it was observed that the Flatlock stitched transmission line and the Double Overlock stitched transmission line have fewer radiation losses compared to the Ric-Rac stitched transmission line. Similarly, the performance of the stitched transmission line when bent through curved angles of 90° and 180° was considered, and a much better 𝑆ଶଵ was observed with a curved angle of 180° for frequencies below 2.1 𝐺𝐻𝑧, with radiation loss increasing afterwards. Finally, the sensitivity of the design to manufacturing tolerances, with changes in cross-sectional dimensions of the stitched transmission line and the transmission characteristics with different textile substrates were both considered. While simulated results showed that the stitched transmission line is sensitive to small variations in its circular dimensions, measured results conversely showed that Denim and Felt materials can be used as a substrate without any significant effect on its propagation characteristics.

Comparative Study Of Changes in SNI 1727 (2013 � 2020) and SNI 1726 (2012 � 2019)

Being one of the largest developing countries, Indonesia has high intensity of infrastructure development. Because of its exact location between the Pacific plate and Eurasian plate, it is necessary to consider the earthquake load in planning a building or other structure. The fundamental period is a function of the lateral stiffness of a building, which will play an important role in carrying lateral loads, such as earthquakes. Earthquake loads experienced by the structure will result in deformation of the building. For building planning in Indonesia, national standards (SNI,) which are continuously adapted to the conditions of the earth and technological developments in construction, are used. This study aims to determine the impact of changes to the standards applied in terms of changes in cross-sectional dimensions, fundamental periods, and building deformation, using modeling in the auxiliary program. Compared with modeling the existing structure in the initial state (model 1), the existing structure with the latest loading (model 2), and the planning results using the latest standard (model 3).Based on the results of the analysis, it was found that the beam dimension changes in the form of an 88% increase in cross-sectional area on the 2nd and 3rd floors of the B9 beam, the largest change in the column cross-sectional dimensions on the K3 column on the 4-7th floor and the K8 column on the 3-7th floor with a large increase of 104%, the change in the fundamental period model 3 increased by 22% from model 1 and increased by 19% from the period model 2, and obtained a change in the form of displacement. X direction in model 3 experienced a maximum increase of 210% against model 1 on the roof floor and in model 3 against model 3 2 increased by 37% on the roof floor for displacement Y direction in model 3 experienced a maximum increase of 192% against model 1 on the roof floor and an increase of 29% against model 2 on the roof.

Innovative method for strengthening dapped-end beams using an external prestressing technique

Dapped-end beams are precast members of concrete structures that are widely used in buildings and bridges. At the end of dapped-end beams, the discontinuities caused by the abrupt changes in cross-sectional dimensions, as well as the concentrated applied load, characterize this as a disturbed region. Improper dimensioning and distribution of reinforcing steel lead to undesirable cracking and failure mechanisms that must be predicted to apply proper strengthening systems. This article presents an experimental program for eight reinforced concrete beams with dapped ends. Seven specimens were strengthened using different shapes of external prestressing technique directions: horizontal, vertical and inclined. A non-strengthened specimen was investigated as a reference beam. The test results showed that vertical external prestressing techniques are a very effective strengthening method to increase the capacity of dapped-end beams up to 82 % compared to the control specimen. A new failure mode according to the strengthening technique using horizontal external prestressing appeared and led to compression failure. Additionally, a comparative study was conducted to evaluate the efficiency of various strengthening techniques. A strut-and-tie model was utilized in the analysis of such discontinuity in the D-region. A comparison between the present strengthening techniques and other previous work was conducted to provide a reasonable estimation of the efficiency of the results.

Impact of oedema on implant geometry and dosimetry for temporary high dose rate brachytherapy of the prostate.

The optimal timing of dosimetry for permanent seed prostatic implants remains contentious given the half life of post-implant oedema resolution. The aim of this study was to establish whether prostatic oedematous change over the duration of a temporary high dose rate (HDR) interstitial brachytherapy (BR) boost would result in significant needle displacement, and whether this change in geometry would influence dosimetry. Two CT scans, one for dosimetric purposes on the day of the implant and the second just prior to implant removal, were obtained for four patients receiving transperineal interstitial prostate brachytherapy. The relative changes in cross-sectional dimensions of the implants were calculated by establishing the change in mean radial distance (MRD) of the needle positions from the geometric centre of the implant for each patient's pair of CT studies. The treatment plan, as calculated from the first CT scan, was used in the second set of CT images to allow a comparison of dose distribution. The percentage change in MRD over the duration of the temporary implants ranged from -1.91% to 1.95%. The maximum change in estimated volume was 3.94%. Dosimetric changes were negligible. In the four cases studied, the degree of oedematous change and consequent displacement of flexiguide needle positions was negligible and did not impact on the dosimetry. The rate and direction of oedematous change can be extremely variable but on the basis of the four cases studied and the results of a larger recent study, it might not be necessary to re-image patients for dosimetric purposes over the duration of a fractionated HDR BT boost to the prostate where flexiguide needles are utilized. Nevertheless, further investigation with larger patient numbers is required.

Strength Prediction for Discontinuity Regions by Softened Strut-and-Tie Model

Discontinuities caused by abrupt changes in cross-sectional dimensions or by concentrated loads result in discontinuity regions due to disturbance in the flow of internal forces. A simplified method, based on the softened strut-and-tie model, for determining the shear strength of discontinuity regions failing in diagonal compressions is proposed in this paper. Strength predictions of the resulting expressions correlate well with the 449 test results of deep beams, corbels, squat walls, and beam-column joints available from the literature. The proposed method incorporates the shear resisting mechanisms as postulated by the softened strut-and-tie model, and it is a function of the concrete strength, horizontal shear reinforcement, vertical shear reinforcement, and geometrical configuration of the discontinuity regions. A numerical example is included for illustration.

Changes in Cross-Sectional Dimensions of Cotton Fibers on Crosslinking and on Subsequent Wetting

Changes in cross-sectional dimensions of cotton fibers resulting from crosslinking treatments were studied. One variety of cotton, Sujata, was subjected to crosslinking in dimethyloldihydroxyethyleneurea and in formaldehyde to different add-on levels. The changes in cross-sectional area and perimeter due to crosslinking, as well as the changes in these dimensions resulting from subsequent wetting, were measured. The results were discussed in the light of available information on fiber morphology and the nature of crosslinking reactions.