Bir hidroelektrik santral binasının projelendirilmesi

Abstract

ÖZET Bu tez çalışmasında bir baraja ait hidroelektik santral binasının statik ve betonarme hesaplan yapılarak yapı projelendirilmiştir. Yapının inşaat oturma alanı 1206.25 m2'dir. Yapının 24.00 m'lik bölümü zemin kotundan aşağıda olmak üzere toplam yapı yüksekliği 32.75 m'dir. Yapı derzlerin ayırdığı 5 bölümden oluşmaktadır. Bu bölümlerin dört tanesi 4'er katlı, bir tanesi ise 2 katlıdır. Yapı içinde birbirine dik olarak işlev gören iki adet kren kirişi bulunmaktadır. Bu krenler türbinlerin oturduğu platformda ve montaj sahasında çalışmaktadır. Yapı dört türbinli bir santral binasıdır. Türbinler düşey eksenlidir. Yapı çevresi kalın perde duvarlarla çevrilidir. Bu perde duvarların içine sızdırmazlık önlemi açısından su tutucular yerleştirilmiştir. Yapının döşeme hesaplarının bir kısmı ile betonarme merdivenleri hesabı dışında kalan statik hesapları SAP 90 statik analiz programı ile yapılmıştır. Yapının temeli elastik zemine oturan kirişsiz radye temel olarak hesaplanmıştır. Betonarme hesapları tamamlanan yapıya ait proje çizimleri ekler bölümünde sunulmuştur. vuı

THE DESIGN PROJECT OF A HYDROELETRIC POWER PLANT SUMMARY The design project of a hydroelectric power plant building presented herein is a master thesis, under administration of Prof. Dr. Nahit KUMBASAR. Building is constructed in the third degree seismic zone according to the map appended to the `Specification for the building to be built in natural diseased areas. Four vertical axes of turbine are located in the power plant. The construction area of the building is 1206.25 m2 having 62.50 m length, 19.30 m width. Building is designed five parts separated by four expansion joints; four parts have four floors and the other has two floors. It consists of a turbine platform floor, a pumping room, a compressor room, a heating and ventilating room, a service room, an oil refining and cooling room and an office floor. The height of the building, only 8.75 m above the earth level, is 32.75 m. As the building is almost under the ground level and high level underground water, the building was surrounded by reinforced concrete walls, consist in water isolation materials to protect the building from shrinkage, flow and dampness. The roof of the building is flat as a terrace roof and it is surrounded by parapet wall, height of 0.90 m. Value of the live loads for the roof was 0.085 t/m2 as snow load. The design of the building starts determining the thickness of the slabs. In order to prevent undesired deflection certain limitations are placed on the minimum slab thickness that can be used in a given floor panel. Floor slabs in building are designed for a uniform distributed loads covering the entire slab area. Distribution of live loads is not constant every floor and it is more than a normal industrial building. So thickness of the plate was chosen as 20 cm for the fourth floor, 30 cm for the third floor and 35 cm for the first and the second floor. IXWorking load of the slab is defined as the sum of the actual dead load of the structure and an estimate of the maximum live load which will be superimposed at same time during its life. Designed loads are obtained by using Turkish Standard 498 (TS 498) combining dead and live loads. In the building slabs are supported by reinforced concrete walls. Slabs are almost supported a long their four sides. Because the ratio of length to width of slab panels were lower than 2, loads being carried by the slab in two direction. With idealised support conditions and assuming a uniform distribution load, the critical forces and moments can be obtained for rectangular slabs from using the method given in Turkish Standard 500 (TS 500) called `An approximating method for slabs bending behaviour one and two ways`. In turbine platform slabs have circular holes. For these slabs, SAP 90 (Structural Analysis Program) is used to obtain the maximum and minimum moments the points of the supports and spans' cross sections. These slabs were supported by the beams; 140 cm height and 50 cm width. At discontinuous edges, negative moments shall be assumed equal to the 56 percent of the positive moments for the same direction. One must provide for such moments, because same degree of restraint is provided discontinuous edges by the torsion rigidity of the edge beam or by the supporting wall. C 20 / S420 is chosen as materials for using reinforced concrete design of the whole system. Reinforcing steel for slabs is placed parallel to the edges for slab span. In continuous slabs, bottom bars are bent up to provide negative bending over the supports. But straight bars reinforcement were used in slabs have circular holes in two directions on the top and bottom. The slabs are reinforced in both directions to resist moments existing in both directions a long two mutually perpendicular layers of bars parallel, respectively, to the two pairs of edges, one layer resting directly on the other. Then, the slabs transmit loads to all four supporting beams or shear walls, the relative amounts depending on the proportions on the slab on the conditions of continuity at the four edges. Since positive moments steel was placed in two layers, he effective height for the upper layer was smaller, than that for the lower layer by one bar diameter. Because the moments in the long direction are smaller, it is economical to place steel in that direction on the top of the bars in short direction.At the fourth section, normal forces of the columns and shear walls are calculated from roof to the foundation by addition. These forces are used to give a initial dimension to the every vertical elements. First every axes are divided into two equal parts in x and y direction and slabs loads, weight of the beams and wall loads were transferred to the connected columns and shear walls. So, normal forces of the vertical elements are found every floor. It is determined that the normal forces are carried by concrete and reinforced concrete steel together in the cross section. In this building, lateral forces are very effective on the reinforced concrete walls The lateral loads and earthquake forces are effectively to determine the thickness of the shear walls, but normal forces gave an idea dimensions of the third and fourth floor columns. At the fifth section, calculations of the beams are done under vertical static loads. First off all, moments of inertia of the beams are calculated and support conditions are determined. Then critical stresses belong to beams' cross section were calculated under concentrated vertical loads. SAP 90 is used for this purpose. Moments, shear forces and normal forces at supports and spans of the beams are given on a table. In design of the cross sections, straight bar reinforcement are used for all spans of the beams. Bottom bar are bent up to provide negative bending over the supports, if the spans of the beams were long enough. Beam stirrups and bend up bars are extended into the slabs. The cross section area of the stirrups is obtained to be sufficient to carry the its tensile force. In this calculations, the carrying capacity of the concrete and bend up steel is neglected. The shear stresses in most beams are far below the direct shear strength of the concrete. The real concern is with diagonal tension stress resulting from the combination of shear stress and longitudinal flexural stress. Shear reinforcement may be provided by bending up a part of longitudinal steel where it is no longer to resist flexural tension. In continuous beams, these bend up bars may also provide all or part of the necessary reinforcement for negative moments. But for short beams in the building, straight bars were placed for supports and spans without bend up steels. At the sixth section, variation of the cross section along the horizontal and vertical elements are found under the lateral earth pressure. Lateral earth pressure was applied for the shear walls multiplied by 1.6. The building set up as a frame shear wall system and calculated under the lateral earth pressures by using SAP 90. Forces are calculated for every floor and forces are assumed to be applied to the building from the midpoint of the every floor slabs. The XIbuilding is supposed to move a shear frame system, so lateral displacements are equal for every point in the same floor. The results of the calculations are taken from the SAP 90 outputs. The superposition of the results of the lateral earth pressure and vertical static loads gave the load condition of 1.4 G + 1.6 Q + 1.6 TT n. The bending moments of shear walls which carry earth pressure are obtained by using SAP 90 program. In this calculation, the shear walls are supported by the slabs at the level of the floor elevation. The solution of the shear walls on which triangular earth pressure are obtained by using the SAP 90, consequently, maximum and minimum CıuSS sctııuıı 5UC35C3 3,1 c ian.cn ııOm me ıCaUıı Oi o.ni- 7U Outputs. At the seventh section, the cross section stresses are calculated under earthquake loads. According to the TS 500, coefficient of the live loads were taken zero because of the earth pressure. This calculations were done for the 0.90 G + 1.0 E load condition. The distribution of the earth pressure is parabolic for earthquake situations in this type of the building. The value of the earth pressure is zero at foundation level and earth surface. Except these points the variation is parabolic. The earth pressure was obtained between every floor elevation by using this parabolic distribution. This calculations are obtained by integrating stresses between every floor and stresses are changed to the forces. Then the value of the lateral earth pressure was multiplied by 0.90 /1. 60 and added to the earthquake situation. Finally, the value of the cross section stresses under the vertical loads are divided by 1.45 and added to the value of stresses under the earthquake loads. So, G + Q + E load obtained and the results given in tables. 1.4G + 1.6 Q + 1.6 H and G + Q + E load conditions were compared for getting maximum and minimum cross section stresses. By using these values, the calculations of the reinforced concrete are done according to the ultimate strength design rules. At the eighth section the crane beams were calculated under static loads. The crane which has 60 ton capacity, is calculated for two `````. ~.,~ ~C *lı-2 T 1 - ft AA - « ~ - »4 *U« /.tk»,,,`` T 1 - O QA T O AT» AA '.~ apaııa, ullc Ox tile L. 1 - /j./j/j hi aııu ıııc Oiiici waa t-it. - o.7l/ 111. jm ?/J 13 used for calculations. Cross section design is made for maximum moment and shear force of the cross section of the crane beams. For reinforced concrete calculations and cross section details, Turkish Standard 9967 is used. Connections of the steels in cross section were supplied by welding where the length of the anchor is not enough. xuAt the ninth section, the stairs of the floors are calculated under the uniformly distributed static loads as a simple beam supporting by slabs. The height is 5.50 m at the third floor, 3.85 m at the second floor and 7.15 m at the first floor. For the first floor, a portable steel stairs is fitted, because there is second step concrete construction on the first floor at the turbine platform floor. Straight bars are used at the bottom for the spans of the stairs slabs and steels were anchored to the floor slabs. The reinforced concrete calculations of the stairs slabs which are placed between two floors, were made same as the floor slabs. At the tenth section, two loads situation ( 1.4 G + 1.6 Q +1.6 H and G + Q +E ) are superimposed. Then, maximum and minimum stresses are obtained for the reinforcement calculations and reinforcement calculations are done for beams, columns, and reinforced concrete walls according to the TS 500. In the reinforcement calculations, firstly, the dimensions of the beams and columns are controlled under this superimposed stresses. It is not necessary to change any dimensions of the elements. The reinforced concrete calculations are made both bending and shearing for the beams and columns. Straight bars were used for the bending and stirrups are placed in the cross section for the shearing. The distance of the stirrups are closed nearing to the supports for the beams. The stirrups are placed in to the columns two types and distance is 10 cm between two stirrups. In the reinforced concrete walls, minimum steel usually obtained from the calculations. Steel bar ratio and bar distance are supplied for every reinforced concrete walls. The distance of the straight bars which placed on vertical, is neared for the two points of the walls to be supplied ductility. At the last section, the raft foundation of the power plant is solved under the concentrated static loads by using SAP 90. It was determined to calculate it as a raft foundation placed on elastic grounu. Allowable earth pressure is 40 t/m2 and coefficient was Ko= 10000 t/rn3. Normal forces and moments are loaded at the bottom end of the columns and reinforced concrete walls as line loads. The results were taken from the SAP 90 outputs. The raft foundation was designed in two steps. One of between 1-12 axes and the other was between 13-15 axes. Thickness of the first step was 2.00 m and the second step was 1.50 m. X1UUnder the results of the SAP 90, reinforcement calculations were done and cross section area of the steel were found for two foundations. Then, straight bars were placed on the bottom and top of the foundation layer for two directions. XIV