Analysis for Pier of Suzhou River Lock Project by 3D-FEM Zhang Yuanyuan Graduate student, Department of Geotechnical Engineering, Tongji University, Shanghai, China.
Contents CONCLUSIONS • Total Deformation • Stress Distribution • Partial Pressure Distribution RESULTS & ANALYSIS • Deformation Result • Stress Result • Distribution Rules under the Function of Concentrated Force MODELING • Calculation Area • Deformation Boundary Condition • Calculation Parameter & Mesh Division • Calculated Loading &Combinations of Loads
INTRODUCTION • Suzhou River Lock Project is located at the bayou of Suzhou River opposite to Jinshan Road, Shanghai, China, of which net width is 102m. To satisfy design requirement, Suzhou River Lock Project should be designed for the function of hydraulic retaining reversibly and water diversion. In detail, its design forward available water head for hydraulic retaining is 3.26m, and its design reversed available water head for tidal retaining is 3.46m.
Design Requirement • Firstly, side pier bears prodigious horizontal thrust and vertical pressure, for mid pier doesn’t provide foundation horizontal restraint for the mat of 99m length and weight 8201ton. • Secondly, it bears prodigious concentrated force and relevant moment, caused by maintaining the lock’s function requirement that allowing the 99m×9.76m strobe rolling over and being fixed freely between 0°and 90°.
1.MODELING OF SIDE PIER • 1.1 Calculation Area According to general experience and concrete geological condition, calculation zone is selected asmuch as 5500mm×5500mm in the calculation flat, of which thickness is 5500mm (along the direction of Z-axis) and height is 5000m (along the direction of Y-axis). (a) Ichnography (b) Elevation view
1.MODELING OF SIDE PIER • 1.2 Deformation Boundary Condition In calculating, the hemline of the pile foundation is seen as fixed boundary, i.e. without any displacement. The backward and forward apron and two sides are treated as plane strain problem, i.e. force added at front and back direction.
1.MODELING OF SIDE PIER • 1.3 Calculation Parameter And Mesh Division • ratio is 1:1. • Concrete pier is simulated by 8-crunode hexahedron mass unit. • steel bracket is simulated by sheet unit. • 16728 = 15440 + 1288 (a) The whole model(b) The whole mesh division (c)Mesh division of concrete(d)Mesh division of steel bracket
1.MODELING OF SIDE PIER • 1.4 Calculated Loading and Combinations of Loads Combination 1(under the function of the peak tidal head): q1+ q2 + q3+ p1+ p2+ deadweight where q1 = gradual hydraulic stress adding at the model’s back side q2 = gradual earth stress adding at the model’s front side q3 = uniform line load adding on the top p1 = two pairs of concentrated force adding on the model’s right side p2 = uniform surface load adding on the top of steel bracket q1 q2 q3 p1 p2
1.MODELING OF SIDE PIER • 1.4 Calculated Loading and Combinations of Loads Combination 2(under the function of the peak operating force): (q1+q2+q3) +（p1+M1）+ deadweight where q1, q2, q3: same as those of combination 1 p1 = concentrated force adding on the top of steel bracket M1 = relevant moment q1 q2 q3 P1+M1
2. RESULTS AND ANALYSIS • 2.1 Deformation Result • According to the deformation result, the deformation of side pier is rather small under the both two combinations of loads. • The rule of combination 1 (under the function of the peak tidal head）is that the deformation inclines horizontally to forward apron and the maximum is -0.67mm. While the rule of combination 2 (under the function of the peak operating force)is that the deformation inclines horizontally to backward apron and the max is 1.1mm. • The inner maximum deformation appears at the combination corner of concrete and steel bracket. 1 2
(a) X-component stress of the pier (b) Y-component stress of the pier 2. RESULTS AND ANALYSIS • 2.2 Stress Result （1） (c) Z-component stress of the pier
2. RESULTS AND ANALYSIS • 2.2 Stress Result （2） Table 2. The MaximumPressure of Reference Concrete Section MPa The maximum value is 24.6Mpa, which satisfies the design requirement. The peak tensile stress of pier’s concrete is 1.93MPa, satisfying the design requirement, too.
2. RESULTS AND ANALYSIS • 2.3 Distribution Rules under the Function Of Concentrated Force （1） While under the function of the peak tidal head, i.e. Combination１, value of the two pairs of concentrated force adding on the model’s right side reaches 11270KN.In calculating, they are divided into X-component and Y-component, and added to the node. Then their distribution rules of stress are gained. (a) Distribution of X-component stress
2. RESULTS AND ANALYSIS • 2.3 Distribution Rules under the Function Of Concentrated Force（2） The maximum Y-component stress appears at the step of concrete (shadow part pointed by arrowhead in Fig(b) ) the shadow part is of 2.4m long, valued as 19.1MPa, located at the intersection point of working point and step (b) Distribution ofY-component stress
3. CONCLUSIONS • The total deformation under the function of its deadweight and operating loads along with level deformation under the function of hydrodynamic head are both so small that the flap gate’s working is not affected. The stress distributions of side pier concrete, bottom of the pit, slope of cushion, pedestrian passage way，front and back wall of Suzhou River lock Project all satisfy the design requirement under two main combinations of loads. The partial pressure distribution under the function of concentrated force satisfies the design requirement, too.
Zhang Yuanyuan Address：Department of Geotechnical Engineering, Tongji University, Shanghai, China(200092) Tel：021-65790471 13585626816 Email: email@example.com Thanks