Deformation Monitoring of The Steel Cylinder of Czersko Polskie – A Historical Weir In Bydgoszcz

S t r e s z c z e n i e Zadaniem jazów jest spiętrzanie poziomów wody w celu tworzenia odpowiedniego spadu do celów energetycznych, utrzymywania stałego poziomu wody, czy zwiększenia głębokości dla żeglugi. Jako budowle zabytkowe, objęte ochroną konserwatorską wymagają okresowych przeglądów stanu technicznego. Celem artykułu jest pomiar geometrii stalowego walca, elementu zabytkowego jazu Czersko Polskie w Bydgoszczy i określenie jego ułożenia w przestrzeni. Ze względu na ograniczoną dostępność powłoki walca – widoczność powierzchni od strony wody dolnej – zaproponowano techniki pomiarowe i procedury obliczeń, które pozwoliły na określenie ułożenia osi walca, jego skręcenie i deformację jego powłoki. K e y w o r d s : Deformation; Geometric assessment; Hydro-engineering structure; Steel structure; Weir. 3/2016 A R C H I T E C T U R E C I V I L E N G I N E E R I N G E N V I R O N M E N T 105 A R C H I T E C T U R E C I V I L E N G I N E E R I N G E N V I R O N M E N T The Si les ian Univers i ty of Technology No. 3/2016 J . S z t u b e c k i , M . M r ó w c z y ń s k a , M . S z t u b e c k a appropriate methods and measuring instruments [7, 8, 9]. This paper presents a method to determine the geometry of the steel cylinder which is the central component of the historical roller dam built in the area of Bydgoszcz where the Brda river flows into the Vistula, on the Czersko Polskie barrage. 2. RESEARCH MATERIAL AND MEASUREMENT METHODS The Czersko Polskie is a damming structure made from steel, concrete and masonry elements supported on a common foundation. It was built at the beginning of the 20th century and is the oldest roller dam in Poland. It is a unique work of hydraulic engineering and its good condition enables continuous operation. The dam is a part of the Vistula-Odra waterway. In Europe, similar types of roller dams can be found in Germany (Griesheim barrage near Frankfurt am Main, or on the Neckar river, near Heidelberg). The Czersko Polskie dams the water of the Brda for the purpose of navigation between Czersko Polskie and the hydro-technical system of Bydgoszcz [10]. It consists of the following elements: – the Czersko Polskie chamber lock, – the roller dam, – a fish pass at the dam (the right abutment), – a hydraulic power plant in the machinery room (left bank), – a hydraulic power plant on the right bank (side spillway), – the 1st junction of the river (out of operation). As it is with any structure of this kind, the roller dam requires routine inspections of its technical condition [11]. In the case of the Czersko Polski the inspection included measurements of the geometry of its main component – the steel drum. The drum, which forms the gate of the dam, is more than 23 m long and has a diameter of 2.5 m. It is supported on two abutments and moved by an electric drive or manually, using a Gall chain mounted on one side of the dam. The drum moves up and down toothed tracks fixed to the two abutments. The structure is shown in Fig. 1. The surface of the steel drum could not be accessed and only a third of this component was visible, which made the choice of the right measuring method and subsequent calculations rather difficult. Therefore, 106 A R C H I T E C T U R E C I V I L E N G I N E E R I N G E N V I R O N M E N T 3/2016 Figure 1. View of the weir from the downstream side Figure 3. Sketch of the object with the location of control points Figure 2. Numbering levels of rivets connecting DEFORMATION MONITORING OF THE STEEL CYL INDER OF CZERSKO POLSKIE – A HISTORICAL WEIR IN BYDGOSZCZ for the determination of the cylinder geometry the characteristic method of connection of its individual structural sections was used. It was assumed that the structure is defined by rows of rivets joining separate sections, which were assessed as parallel to the axis of the cylinder. Out of the six lines of rivets placed along the generating lines of the drum, visible from the downstream side, three were selected for control measurements: No. 1, No. 3 and No. 5 (Fig. 2). The numbering sequence was related to the levels of rivets and the drum structure. At the top level, 26 control points were selected, 35 at the middle one and 36 at the bottom (Fig. 3). The object was measured twice: on 24 October 2012 for the first time, using a Topcon GTS 212 Total Station, and on 12 May 2014 for the second time, using a Topcon IS imaging station to verify the initial measurements. The first measurement was taken of the three sites using the angular intersection. The second measurement was taken of the two sites by tachymetry. The possibility of using reflectorless distance measurement shortened of the measurements duration twice. Total Station Topcon IS also allows the initial, automatic pointing to the measured point in reading from right. It is affected on avoiding errors. For each campaign, the instrument was placed on both sides of the dam. During the first campaign, horizontal and vertical directions were observed for the control points, whereas the second campaign also included the observation of the distances. 3. CALCULATION METHODS AND THE DISCUSSION OF RESULTS On the basis of the above assumptions, in the first phase spatial coordinates of the control points were determined in a local system. Presuming that the drum has a uniform distribution of the rivets, threes of points forming triangles in perpendicular cutting planes were selected. The triangles are shown in Fig. 4. Next, the coordinates of the geometric centres of these triangles were determined. In the second phase of calculations the system was transformed into one, in which: – Y axis is parallel to the straight line crossing the geometric centres of the first and the last triangle, – X axis forms a frame of reference with Y axis, – Z coordinates are not altered. 3.1. Torsional deflection of the cylinder Assuming that corresponding sides of adjacent triangles in the perpendicular planes are parallel, the shift of them was determined, which allowed the determination of the torsional deflection of the drum. A positive twist was assumed for the direction of the water flow (i.e. in the downstream direction). The values of the established torsional deflection are shown in Table 1. The obtained values of the angle of twist for both control measurements are comparable. This indicates that the drum did not undergo further twisting. Looking towards the NW abutment, the positive value of twist implies that the deflection follows the direction of the down flow. The average torsional deflection, with reference to the whole length of the drum, amounted to 0.90g (0.81°), which corresponds to an 18 mm twist along its circumference. 3.2. Inclination of the cylinder In order to determine the inclination of the steel drum for each of the control points, the difference between individual values of the Z coordinate was established in relation to the initial point at each level. The changing values of Z are shown in diagrams in Figures 5, 6 and 7. C I V I L E N G I N E E R I N G e 3/2016 A R C H I T E C T U R E C I V I L E N G I N E E R I N G E N V I R O N M E N T 107 Figure 4. Cylinder view with an indication of the lines where selected control points and triangles Table 1. Angle of cylinder torsion Cylinder torsion angle