The Horizontal Deformation Analysis of High-rise Buildings

Transcription

1 Environental Engineering 10th International Conference eissn / eisbn Vilnius Gediinas Technical University Lithuania, April 2017 Article ID: enviro DOI: The Horizontal Deforation Analysis of High-rise Buildings Žyantas Gražulis 1, Boleslovas Krikštaponis 2, Algirdas Neseckas 3, Darius Popovas 4, Raiundas Putrias 5, Doinykas Šlikas 6, Evelina Zigantienė 7 Vilnius Gediinas Technical University, Vilnius, Lithuania E-ails: zyantas.grazulis@stud.vgtu.lt (corresponding author); boleslovas.krikstaponis@vgtu.lt; algirdas.neseckas@vgtu.lt; darius.popovas@vgtu.lt; raiundas.putrias@vgtu.lt; doinykas.slikas@vgtu.lt; evelina.zigantiene@vgtu.lt Abstract., quite often is coplicated because buildings like chineys, towers and etc, have coplex and asyetric shapes, consequently there is not always the possibility to apply the ethod of single points otion analysis. Furtherore, the horizontal deforation analysis is coplicated using standard easureent ethods like easureents with electronic total stations or optical theodolites. In such case the terrestrial laser scanner could be superior to traditional easureents. However, the terrestrial laser scanner still not widely used to survey building horizontal deforations using high precision easureents. The ain ai of this work is to deterine the suitability to easure deflections of buildings fro the vertical using terrestrial laser scanners and to investigate point cloud data processing. Measureents of horizontal deforation were carried out using the over ground laser scanner and electronic total station. Horizontal deforations of chineys of theral power plants were investigated using corresponding ethods. Deforation indicators and evaluated easureent accuracies between different ethods were copared. Data analysis of terrestrial laser scanning is ore coplex, tie consuing and requires sophisticated hardware resources in coparison with the traditional ethods, however results are uch ore detailed and inforative. Keywords: deforations, vertical deflection of buildings, terrestrial laser scanner, geodetic observations. Conference topic: Technologies of geodesy and cadastre. Introduction Deforation easureents of large structures, especially building tall buildings (chineys, cooling towers, television towers and poles, water towers, etc.) are one of the ost iportant issues of surveying engineering. A chiney is a necessary part of a heat-producing plant, a refinery and any other types of industrial buildings. It poses potential dangers for huan safety and property because if it collapses, it ay cause ieasurable daage to huan lives and wealth. It is essential to onitor and easure the chiney deforation on a regular basis. The ain task of the deforation easureent is to easure inclination of the centerline of a chiney fro the vertical, while it only can be deterined indirectly (Zheng et al. 2012). Measureent devices and techniques in this field are ainly based on the onitoring of discrete points (Kregar et al. 2015). Despite of the developent of the innovative onitoring engineering techniques, in practice, traditional easureent ethods are still widely used. Besides classical techniques, for the recording of surfaces nowadays laser scanners are used, which acquire dense point clouds in very short tie (Uchański, Soerensen 2010). Sall-scale deforation onitoring using terrestrial laser scanning is gaining considerable attention ainly due to the high spatial resolution of the acquired data (Tsakiri et al. 2006). As highlighted in nuerous previous research works, TLS can provide surveyors with the eans to conduct far ore coplete (dense) easureents in relatively short tie. This would lead to ore reliable diensional control results, despite the fact that single point precision is ostly not sufficient (Girardeau-Montaut et al. 2005; Park et al. 2007). It appears that precision potential in these applications is not liited by the single point accuracy of laser scanners, since surface eleents derived fro a large nuber of points are used for deforation analysis (Tang et al. 2010; Bosche, Haas 2008; Schneider 2006). In article, we present a coparison of TLS and classical deforation easureent of two chineys. In TLS approach the point cloud was cut into thin layers and projected onto 2D planes in different height levels. Then a cylinder-fit algorith was applied to these cross section point clouds, where the center points of the cylinders have a uch higher precision than single laser scanner points (Akca 2004). The connection of center points of these cylinders at different heights represents the centerline (axis) of the chiney. The coparison with the results fro total station easureents also presented Žyantas Gražulis, Boleslovas Krikštaponis, Algirdas Neseckas, Darius Popovas, Raiundas Putrias, Doinykas Šlikas, Evelina Zigantienė. Published by VGTU Press. This is an open-access article distributed under the ters of the Creative Coons Attribution (CC BY-NC 4.0) License, which perits unrestricted use, distribution, and reproduction in any ediu, provided the original author and source are credited.

2 Measureent ethods and research object The research object is two chineys of joint-stock copany Vilniaus energija in sall town Trakų Vokė. The height of both chineys are about 20 and the diaeters at the botto are 0,74 and 0,94 respectively. Chineys are part of heat producing facility located in Trakų Vokė. To establish the geodetic control network for chineys deforation onitoring the bencharks were easured with GNSS receivers using LITPOS continuously operating GNSS stations network data as reference stations. For classical horizontal deforation easureents electronic total station Leica TCRP1200+, with angular accuracy of 1ʺ was used, and for TLS easureents laser scanner Leica Scanstation C10 with angular accuracy of 12ʺ was tested. In ost cases, deforation onitoring is perfored by using electronic total stations. First of all the exact coordinates and heights of the onitoring bencharks are derived and adjusted using geodetic ethods. Fro these bencharks the cross-sections at selected heights are easured. It is iportant that easureents fro all stations is perfored bisecting the sae height (cross section) of the chiney. Chiney deforation is reflected by center displaceent of each chiney cross-section. Measureents were carried fro two stations at 6 cross-sections evenly distributed along the chiney (Fig. 1). Terrestrial laser scanning is considered faster and ore progressive geodetic easureent ethod. The terrestrial laser scanner position and orientation was set using three high reflective targets. Position of these targets was easured with electronic total station fro the sae geodetic control network points used in classical approach. The targets were positioned in a way that they will be visible fro both easuring stations, and provided good geoetric distribution for scanner position deterination. Observations with the terrestrial laser scanner covered whole chineys, not just chosen cross-sections (Fig. 2). Fig. 1. Measureent setup using electronic total station Fig. 2. Measureent setup using terrestrial laser scanner Processing of easureent data. The observed chineys have cylindrical shape, therefore cross-sections has a circular for. In order to deterine deviations fro the vertical it is necessary to calculate the centers of the circles of each cross-section fro easured points. The circle center coordinates are calculated according to the following forulas. Circle arc points and the coordinates of the center can be linked with the radius by the equation: + =. Here and coordinates of chiney surface points in the corresponding cross-section, ir the coordinates of a center of the cross-section, R radius of the chiney cross-section. After perforing soe atheatical operations: = 0; = 2 ; = 2 ; = + ; = +. 2

3 For each easured point we receive correction equation: = + +. Applying correction equations for each easured point and using the least squares approach to find unknowns _ we can estiate radius and center coordinates of the circle: = = ; 2 = + 4. Using the forulas above, cross-section center coordinates of both chineys was calculated and chineys deviations fro the vertical were estiated. Deviations were estiated in each cross-section with respect to the lowest cross-section. In each cross-section 8 surface points of the chiney were easured using total station. Estiated vertical deviations of the chineys fro total station easureents presented in tables 1 and 2, and figure 3 and 4. No. Table 1. Vertical deviations of chiney No.1 (total station easureents) height fro the chiney base Deviation fro the vertical, Aziuth botto 154,36 0, SE NE NE NE NE top = = = = = Discrepancys in x axis Discrepancys in y axis Discrepancys in plan Fig. 3. Vertical deviations of chiney No. 1 (total station easureents) 3

4 No.. Table 2. Vertical deviations of chiney No. 2 (total station easureents) height fro the chiney base Deviation fro the vertical, Aziuth botto SE SE SE NE NE top = = = = = Discrepancys in x axis Discrepancys in y axis Discrepancys in plan Fig. 4. Vertical deviations of chiney No. 2 (total station easureents) Measureents with terrestrial laser scanner were perfored with density 1point/1 2 across all surface of the chiney. Fro the point cloud 8 thin layers in different height levels (the sae heights as total station easureents) was cut and center coordinates of these point cloud cross-sections were estiated. Center coordinates of each crosssection were coputed fro around one thousand points. Estiated vertical deviations of the chineys fro TLS easureents presented in tables 3 and 4, and figures 5 and 6. No.. Table 3. Vertical deviations of chiney No.1 (TLS easureents) Cross-section height fro the chiney base Deviation fro the vertical, Aziut h botto

5 End of Table SW NE NE NE NE top = = = = = Discrepancys in x axis Discrepancys in y axis Discrepancys in plan Fig. 5. Vertical deviations of chiney No. 1 (TLS easureents) No.. Table 4. Vertical deviations of chiney No. 2 (TLS easureents) height fro the chiney base Deviation fro the vertical, Aziuth botto SE SE E NE NE top 173,92 19,42 5

6 31 20 = = = = = Discrepancys in x axis Discrepancys in y axis Discrepancys in plan Fig. 6. Vertical deviations of chiney No. 2 (TLS easureents) In the tables above, the center coordinates of the cross-sections expressed in LKS94 coordinate syste, noral heights in LAS07 height syste and the relative heights of the chiney expressed in relation with the botto of the chiney. There are coordinate differences (chiney deviations fro the vertical) in x and y coponents and linear deviation presented as well. Coparison of the results We copared estiated chiney deviations of the vertical fro different easureent ethods. Deviation deterination was done using the two ethods and assuing that they have ore less sae accuracy, chiney deviation accuracy assessent was carried out by double easureents differences. =, where: differences of double easureents, n nuber of differences. It is also possible to calculate the deviations fro the averages fro the two ethods, then the ean squared error of the deviation is: = / 2. Deviation accuracy assessents presented in tables 5 and 6. Cross-section No. Deviation fro the vertical fro total station easureents, Table 5. Deviation accuracy assessent of chiney No.1 Deviation fro the vertical fro TLS easureents, Differences of deviations Σ

7 Table 6. Deviation accuracy assessent of chiney No. 2 Cross-section No. Deviation fro the vertical fro total station easureents, Deviation fro the vertical fro TLS easureents, Differences of deviations Σ Differences in chiney deviation results do not exceed 4. The calculations shows that root ean square (RMS) error is less than 2 then single ethod is used, and RMS error does not exceed 1.4 then the average of the both ethods is used. Conclusions 1. The analysis and coparison of deviation results suggests that TLS is suitable tool for deforation onitoring 2. A easureent with terrestrial laser scanner allows ore precisely deterine the center of the cross-section due to huge aount of points, despite the fact that single point precision is lower than total station. 3. Using point cloud data we can calculate any required cross-section at any height. Overall scan creates uch ore detailed and coplete data set. References Akca, D A new algorith for 3D surface atching, in 20th ISPRS Congress, Istanbul, Turkey, July 12 23, International Archives of the Photograetry, Reote Sensing and Spatial Inforation Sciences XXXV, part B7: Bosche, F.; Haas, C. T Autoated retrieval of 3D CAD odel objects in construction range iages, Autoation in Construction 17(4): Girardeau-Montaut, D.; Roux, M.; Marc, R.; Thibault, G Change detection on point cloud data acquired with a ground laser scanner, in G. Vosselan, C. Brenner (Eds.). International Archives of Photograetry XXXVI, Part 3/W19. ISPRS Workshop Laser scanning 2005, Enschede (The Netherlands). Kregar, K.; Abrožič, T.; Kogoj, D.; Marjetič, A Deterining the inclination of tall chineys using the TPS and TLS approach, Measureent 75: Park, H. S.; Lee, H. M.; Adeli, H.; Lee, I A new approach for health onitoring of structures: terrestrial laser scanning, Coputer Aided Civil and Infrastructure Engineering 22(1): Schneider, D Terrestrial laser scanning for area based deforation analysis of towers and water dans, in Proceedings of 3rd IAG/12th FIG Syposiu, Baden, Austria, May, Tang, P.; Huber, D.; Akinci, B.; Lipan, R.; Lytle, A Autoatic reconstruction of as-built building inforation odels fro laser-scanned point clouds: a review of related techniques, Autoation in construction 19(7): Tsakiri, M.; Lichti, D.; Pfeifer, N Terrestrial laser scanning for deforation onitoring, in 3 rd IAG/12 th FIG Syposiu, Baden, May 22 24, Uchański, Ł. and Soerensen, L Technology of terrestrial laser scanning in probles of reverse engineering and dynaic process analysis, Archiwu Fotograetrii, Kartografii I Teledetekcji 21, 2010: Zheng, S.; Ma, D.; Zhang, Z.; Hu, H.; Gui, L A novel easureent ethod based on silhouette for chiney quasi-static deforation onitoring, Measureent 45(3):