Content
Characters used in the design of reinforced concrete structures INTRODUCTION
CLASSIFICATION AND SCOPE OF CONCRETE STRUCTURES CHAPTER 1. PHYSICAL AND MECHANICAL PROPERTIES OF
CONCRETE, reinforcing steel 11
concrete classification 12
concrete structure 19
concrete strength 19
class and grade of concrete… 21
12. Armature 24
CONTROL QUESTIONS 33
Chapter 2. Features CALCULATION ELEMENTS CONCRETE STRUCTURES
Calculation of structures for limit states 34
Calculation of reinforced concrete elements for limit states of the first group
……………………………………………………………..……………………34
Normative and calculated resistance materials 35
Effects of stress on concrete structures 37
to crack resistance of reinforced concrete structures Requirements
Losses pre-stresses in the armature 39
Calculation of reinforced concrete elements for limit states of the second group 46
CONTROL QUESTIONS
Chapter 3. CALCULATION OF STRENGTH bent elements
Scope and types of bent elements 47
Strength calculation on the normal section 49
Calculation of rectangular cross-sections with a single armature… 51
Calculation of rectangular sections with a double armature 57
Calculation of T -sections 60
CONTROL QUESTIONS. 63
Chapter 4. CALCULATION OF STRENGTH bent elements of oblique sections
. The strength of the inclined section to the effect of shear forces 64
. Calculation of the strength of the inclined section to the effect of shear forces 66
4.3. Calculation of the strength of the inclined sections of the action of bending moment 70
CHECKLIST 74
Chapter 5. CALCULATION OF STRENGTH struts
Scope and types of compression and tension members 75
Calculation of the strength of the central struts 77
Calculation of the strength of the compressed elements at design eccentricities 79
Central tension member. Applications and types of tension members 82
Stress state central tension members 85
Calculation of the strength of the central and eccentrically stretched elements 86
CHECKLIST 87
Chapter VI . Overloaded elements of calculation and design principles 88
The essence of pre-stressed concrete 88
Methodsofpre-stressing 88
Themain rule of the design of pre-stressed elements 90
Strained state due to the influence of external forces before the normal section of the tendon 92
Calculation of pre-stressed elements bent on limiting conditions of the first group 94
Calculation of pre-stressed tension members the central limit state of the first group 94
Bob. Multilayer structures 95
Design and application of concrete multilayer structures 95
Construction of sandwich panels 97
Sandwich panels with flexible connections 97
Three-layer reinforced concrete panels with cast-related layers 102
The essence of the design of three-layer structure 104
The three-layer wall panels with flexible connections and effective insulation 104
Accounting for joint work in the elastic layers of the stage 104
Calculation of bent multilayer monolithic elements section 107
The cost-effectiveness of three-layer wall panels 108
Tasks to decision 111
Calculation and design multivacuum panel 111
. Design precast concrete columns 115
. Calculation Central loaded bases under columns 121
Design of roof construction 125
. General information 125
.Team roof panels with a length of 6 m and 3 m width 126
.Folding roof girder with length arch 6 M 142
.Folding roof girder with length arch 9 m 151
Literature 168
KIRISH
Respublikamiz iqtisodiyotining rivojlanishida ilmiy-texnik taraqqiyotining jadalligi muhim rol o‘ynaydi.
Ilmiy-texnik taraqqiyotni jadallashtirish uchun qurilish yuqori texnologik jarayonida aylantirish, zavod sharoitida tayyorlanadigan qurilish buyumlari va konstruksiyalarini tayyorlashda yuqori mustahkamlikka ega bo‘lgan ashyolar ishlatish evaziga va ularning sifatini oshirish, loyihaviy va qurilish ishlarining narxini kamaytirish va texnik-iqtisodiy ko‘rsatkichlarini yaxshilash hamda ob’ektlarni barpo qilish muddatini qisqartirish talab etiladi.
Zamonaviy qurilish temirbetonsiz tasavvur qilib bo‘lmaydi. Temirbeton keng ko‘lamda qo‘llaniladigan poydevorlar, to‘sin, ustun va to‘siq konstruksiyalarini tayyolashda ishlatiladi.
Mazkur darslik “Qurilish materiallari, buyumlari va konstruksiyalari ishlab chiqarish”, yo‘nalishi va “Bino va inshootlar qurilishi” yo‘nalishlari va mutaxassislaklari dasturiga moslab yozilgan. Darslikni asosiy maqsadi bo‘lg‘usi qurilish konstruksiyalarini ishlab chiqarish texnologiyasi mutaxassislariga temirbeton konstruksiyalarini loyihalash va hisoblashning asosiy prinsiplarini o‘rgatishdan iboratdir. Konstruksiyalarning mustahkamligi, bikrligi hamda ko‘pga chidamlilik sifatini oshirish asosiy vazifa va talabalardan biri hisoblanadi.
Hozirgi davrda qurilish konstruksiyalarini jadal su’ratda rivojlantirish uchun ularni hisoblashda va loyihalashda usullarini takomillashtirish talab etiladi.
Zavod sharoitida tayyorlanadigan qurilish konstruksiyalarini loyihalashda zamonaviy elektron hisoblash mashinalardan foydalanish,
konstruksiyalarining ishchi chizmalarini tayyorlashda zamonaviy dasturlardan foydalanish injener-texnik xodimlarning ishini ancha engillashtiradi.
Ma’lumki beton siqilishda yaxshi, cho‘zilishga esa yomon qarshilik ko‘rsatadigan sun’iy tosh materiali hisoblanadi. Betonning siqilishga bo‘lgan mustahkamligi cho‘zilishga nisbatan 15-20 marotaba ko‘pdir. Betonning cho‘zilishdagi qarshiligi kam bo‘lganligi sababli betondan tayyorlangan konstruksiyalar egilishga ko‘p yuk ko‘tara olmaydi. Egiladigan beton elementning cho‘zilish zonasiga armatura joylashtirilsa, elemenetning mustahkamligi keskin oshadi. Armatura siqilishga ham cho‘zilishga ham yaxshi qarshilik ko‘rsatganligi tufayli cho‘ziladigan, siqiladigan hamda egiladigan elementlarning yuk ko‘tara olish qobilyatini oshiradi.
Tanasining armatura joylashtirilgan beton konstruksiyalar temirbeton konstruksiyalar deb ataladi.
Beton va temirbetondan tayyorlanadigan konstruksiyalarining qurilishdagi salmog‘i boshqa materiallardan tayyorlangan konstruksiyalarga nisbatan ancha katta bo‘lganligi sababli unga katta e’tibor berilmoqda. Temirbetondan tayyorlanadigan konstruksiyalar takomillashtirilmoqda. Olim va injenerlarning keng ko‘lamda olib borayotgan taqdiqiqotlari asosida temirbeton nazaryasi rivojlanmoqda va yangi ma’lumotlar bilan to‘ldirilmoqda. Hisoblash uslubi takomillashtirilmoqda va temirbeton konstruksiyalarni hisoblashda elektron hisoblash mashinlari (EHM) qo‘llanilmoqda. Natijada temirbeton konstruksiyalarini loyihalashning me’yori yangilandi va qo‘llanmalar ishlab chiqilmoqda.
Darslik temirbeton konstruksiyalarini tayyorlash uchun qo‘llaniladigan beton va armaturalar haqida ma’lumot, temirbeton konstruksiyalarining elementlarini chegaraviy holatlar bo‘yicha hisoblash uslubi va ishonchlilikka hisoblash asoslari yoritilgan. Egiladigan, markaziy va nomarkaziy siqiladigan hamda markaziy va nomarkaziy cho‘ziladigan, mahalliy siqilishga ishlaydigan hamda murakkab kuchlanish holatida ishlaydigan elementlarni hisoblash va loyihalash asoslari keltirilgan.
Temirbeton hamma sohalardagi zamonaviy qurilishlarda keng qo‘llanilmoqda, chunki u chidamli, mahalliy qurilish materiallaridan foydalanish mumkin, metall tejamli sarflanadi, ko‘rinishi salobatli va turli shakllarga ega. Qurilishda quyma, yig‘ma va yig‘ma-quyma temirbeton qo‘llanadi. Quyma temirbeton qurilmasi qurilishda loyiha ko‘rinishida tayyorlanadi. Undan kam takrorlanuvchi va bo‘linishi (ajratilishi) qiyin bo‘lgan inshootlar bunyod etiladi. Quyma temirbetondan qurilgan inshootlatga hohlagan ko‘rinishni berish mumkin, ular mustahkam va metall sarf bo‘lishi jihatdanidan anchagina tejamlidir.
Temirbeton konstruksiyalar bir necha turga bo‘linishi mumkin:
a) qo‘llanishiga ko‘ra – turar joy, sanoat, qishloq va suv xo‘jaligi qurilishi, transport, energetik qurilish va boshqalar;
b) materialiga ko‘ra – og‘ir betondan, g‘ovak to‘ldiruvchili betondan va uyasimon betondan:
v) bajarilish usuliga ko‘ra – yaxlit, bevosita qurilish ob’ektlarida barpo qilinadigan; yig‘ma, zavod va poligonlarda tayyorlanadigan; yig‘ma– yaxlit, bir qismi yig‘ma elementlardek tayyorlanib, qurilish ob’ektlarida yaxlit beton yordamida loyihaviy o‘lchamlarga etkaziladigan konstruksiya;
g) armaturalash usuliga ko‘ra – oddiy armaturlash (sinchlar, turlar va alohida sterjenlar bilan) va yuqori mustaqamli armaturalar bilan ularni oldindan zo‘riqtirib armaturalanadi.
Konstruksiyalarda armaturaning beton bilan birgalikda ishlashini ta’minlaydigan omillar quyidagilardan iborat:
qotish jarayonida beton va po‘lat armatura bir–biriga maxkam yopishadi;
zich beton po‘lat armaturani zanglashdan va yong‘indan asraydi;
armatura va betonning temperatura ta’sirida chiziqli kengayish koeffitsientlari bir–biriga juda yaqin (beton uchun bT=(1…1,5)10–5; armatura uchun esa bT=1,2x10–5.
Bu omillar temirbetonning ishlab chiqarishda keng qo‘llanishini ta’minlaydi. Har qanday material kabi temirbeton ham afzalliklar va kamchiliklarga ega.