RAILWAY CONCRETE SLEEPER
[CODE NO.4203]
Sleepers are members generally laid transverse to the rails on which the rails are supported and fixed, to transfer the loads from rails to the ballast and subgrade below. Sleepers perform the following functions:
i. To hold the rails to correct gauge (exact in straight and flat curves, loose in sharp curves and tight in diamond crossings).
ii. To hold the rails in proper level transverse tilt i.e., level in turnouts, crossovers, etc., and at 1 in 20 tilt in straight tracks, so as to provide a firm and even support to rails.
iii. To act as elastic medium in between the ballast and rails.
iv. To distribute the load from the rails to the index area of ballast underlying it or to the girders in case of bridges.
v. To support the rails at a proper level in straight tracks and at proper super elevation on curves.
vi. Sleepers also add to the longitudinal and lateral stability of the permanent track on the whole.
vii. They also provide means to rectify track geometry during service life.
For good performance of sleepers to fulfill the above functions or objectives an ideal sleeper should possess the following characteristics:
i. The sleepers to be used should be economical, i.e., they should have minimum possible initial and maintenance costs.
ii. The fittings of the sleepers should be such that they can be easily adjusted during maintenance operations such as easy lifting, packing, removal and replacement.
iii. The weight of sleepers should not be too heavy or excessively light, i.e., they should have moderate weight, for ease of handling.
iv. The design of sleepers should be such that the gauge, alignment of track and levels of the rails can be easily adjusted and maintained.
v. The bearing area of sleepers below the rail seat and over the ballast should be enough to resist the crushing due to rail seat and crushing of the ballast underneath the sleeper.
vi. The sleeper design should be such as to facilitate easy removal and replacement of ballast.
vii. The sleepers should be capable of resisting shocks and vibrations due to passage of heavy loads of high-speed limits.
viii. The design of the sleepers should be such that they are not damaged during packing processes.
ix. The insulation of rails should be possible for track circuiting, if required, through sleepers.
Prestressed concrete is the concrete in which permanent internal stresses are deliberately introduce, usually by tensioned steel, to counteract to the designed degree, the stresses caused in the member in service.
Pre-tensioning is the method of prestressing concrete in which the tenons are tensioned before concreting. Whereas post-tensioning is the method of prestressing concrete in which prestressing steel is tensioned against the hardened concrete. Initial tension is the maximum stress induced in the prestressing tenon at the time of the stressing operation and initial prestress is the stress in the concrete at transfer. Although the first experiments were made in USA and the first patent for prestressed concrete was issued in 1988 for P.H. Jackson of Sanfransisco, it was developed in Europe. French, German & Danish engineers tried various ways of prestressing concrete, but none was successful till 1930 when in France, the high strength steel wire was used for prestressing concrete. After 1950s, actually, the prestressed concrete has found its major uses in fabricated constructions where it can be shop controlled & tested. Lift slab constructions were precast or cast on-site. Today it can be well seen that prestressed concrete is finding its varied uses in various types of constructions.
Prestressed concrete sleepers are now being increasingly used by most of the railways throughout the world in preference to timber ones because of scarcity of timber and the inherent technical advantages of concrete sleepers for use with long welded tracks carrying heavier axle loads and designed for greater speeds. The superior structural properties of concrete sleepers add considerably to the overall stability and better performance of the total track-structure. Concrete sleepers with their elastic fastenings also provide better safeguard for important track parameters, such as, gauge, cross levels form of twist, alignment etc. as compared to other types of sleepers. Of the several types of concrete sleepers in use, survey indicates that a majority of them, as much as 70% are monoblock prestressed concrete sleepers.
COST ESTIMATION
Plant Capacity 1000 Nos/Day
Land & Building (10,000 sq.mt.) Rs. 4.03 Cr
Plant & Machinery Rs. 3.80 Cr
Working Capital for 1 Month Rs. 4.91 Cr
Total Capital Investment Rs. 13.02 Cr
Rate of Return 35%
Break Even Point 50%
- INTRODUCTION
- CLASSIFICATIONS OF SLEEPERS
- TYPES OF PSC SLEEPER
- A. MONO BLOCK CONCRETE SLEEPERS (MBC):
- B. TWIN BLOCK CONCRETE SLEEPERS:
- IMAGES
- FIG. 1: MONO BLOCK CONCRETE SLEEPER
- FIG. 2: TWIN BLOCK CONCRETE SLEEPER
- PSC SLEEPER AND ITS FUNCTION
- FUNCTIONS
- DESIGN CONSIDERATION FOR PRESTRESSED CONCRETE SLEEPERS
- DESIGN AND MODELLING OF CONCRETE SLEEPERS
- SLEEPER SECTION:
- MATERIAL PROPERTIES:
- PRESTRESSED CONCRETE SLEEPERS
- THE DESIGN IS BASED ON:
- USES AND APPLICATION
- CAUTIONS
- B.I.S. SPECIFICATION
- RUSSIAN
- HUNGARIAN
- OTHER FOREIGN STANDARDS
- STANDARD FOR M.I. FITTINGS SPECIFICATIONS
- RAW MATERIALS
- BEND TEST
- REVERSE BEND TEST
- GAUGE CONVERSIONS
- B. HIGH STRENGTH CONCRETE MIXES FOR PRESTRESSED CONCRETESLEEPERS
- CONSTIUENTS OF CONCRETE
- MATERIALS AND THEIR EFFECTS
- CEMENT
- AGGREGATES
- COARSE AGGREGATE
- FINE AGGREGATE
- ULTRAFINES
- WATER
- ADMIXTURES
- ACCELERATORS
- RETARDERS
- WORKABILITY AGENTS
- AIR-ENTRAINING AGENTS
- WATER REPELLING AGENTS
- GAS-FORMING AGENTS
- GENERAL PRINCIPLES OF MIX DESIGNS
- DESIGN OF HIGH STRENGTH CONCRETE
- GENERAL
- TABLE - SUGGESTED RANGES OF VALUES OF WORKABILITY OF CONCRETE FOR DIFFERENT PLACING CONDITIONS
- TABLE - MINIMUM CEMENT REQUIRED IN CEMENT CONCRETE TO ENSURE DURABILITY UNDER SPECIFIED CONDITIONS OF EXPOSURE
- REQUIREMENTS FOR PLAIN AND REINFORCED CONCRETE EXPOSED
- TO SULPHATE ATTACK
- MINIMUM CEMENT CONTENT REQUIRED IN CEMENT CONCRETE TO ENSURE DURABILITY UNDER SPECIFIED CONDITIONS OF EXPOSURE
- FOR PRESTRESSED CONCRETE
- TABLE - REQUIREMENTS FOR PRESTRSSED CONCRETE EXPOSED
- TO SULPHATE ATTACK
- TABLE LIMIT FOR CHLORIDE ION IN CONCRETE PRIOR TO EXPOSURE
- IN SERVICE
- ENTROPY AND SHAKLOK METHOD
- (I) SELECTION OF STRENGTH FOR THE DESIGN OF MIX
- (II) SELECTION OF WORKABILITY
- (III) WATER - CEMENT RATIO
- (IV) AGGREGATE - CEMENT RATIO
- (V) DETERMINATION OF PROPORTION OF FINE & COARSE AGGREGATES
- EXAMPLE NO.1:
- SIEVE ANALYSIS OF 6-10 MM SIZE AGGREGATES
- SIEVE ANALYSIS OF 10-12 MM SIZE AGGREGATE
- SIEVE ANALYSIS OF 12-10 MM SIZE AGGREGATE
- WEIGHT OF CEMENT FOR ONE CUBIC OF CONCRETE = 502 KG
- CEMENT
- HIGH TENSILE STEEL
- CONCRETE
- RESEARCH & DEVELOPMENT
- MODERN DEVELOPMENTS IN THE DESIGN & CONSTRUCTION ASPECTS
- VACUUM CONCRETE
- DESIGN CONSIDERATIONS FOR PCC SLEEPERS
- DESIGN LOADS
- SALIENT FEATURES OF PCC SLEEPERS
- SLEEPER DENSITY
- EXAMPLE
- OVERVIEW OF CONCRETE SLEEPER PLANT
- PRODUCTION POSITION OF CONCRETE SLEEPER PLANTS
- THE RANGE OF MANUFACTURING IS AS FOLLOWS:
- THE CONCRETE SLEEPERS MANUFACTURED BY THESE COMPANIES ARE SUITABLE FOR:
- POLICY OF CONCRETE SLEEPER PLANT IN INDIAN RAILWAY
- GOVERNMENT OF IND MINISTRY OF RAILWAYS (RAILWAY BOARD)
- SUB: REVISED POLICY FOR CONCRETE SLEEPER PLANTS ON INDIAN
- RAILWAYS
- 1.1 POLICY ON SHIFTING OF SLEEPER PLANTS
- 1.2 POLICY ON SETTING UP OF NEW CONCRETE SLEEPER PLANT (CSP)
- QUALIFYING REEQUIREMENTS:
- OTHER TERMS AND CONDITIONS:
- EASTERN DEDICATED FREIGHT CORRIDOR PROJECT
- INDIAN RAILWAY GROWTH AND FUTURE PROSPECTS
- MARKET SIZE
- INVESTMENTS/ DEVELOPMENTS
- FEW RECENT INITIATIVES TAKEN UP BY THE GOVERNMENT ARE:
- PROMINENT MANUFACTURERS PROFILE OF RAILWAY SLEEPER
- LOCATIONS
- PRESENT MANUFACTURE OF PRESTRESSED CONCRETE RAILWAY SLEEPER
- PROCESS WISE EQUIPMENT DESCRIPTIONS
- AGITATIONS
- THE FREE FULL MIXER ARE OF THE FOLLOWING TYPES:-
- AUTOCLAVE CURING
- THE FORM WORK
- PRESTRESSING APPARATUS
- 1.TENSIONING APPARATUS
- TESTING OF CONCRETE MIXES
- SAMPLING & TESTING OF CONCRETE
- APPARATUS FOR TESTING
- METHODS OF MANUFACTURE AND TESTS FOR ACCEPTANCE
- PRODUCTION OF PRE-TENSIONED SLEEPERS:-
- 1.LONG-LINE METHOD
- STRESS-BENCH METHOD (4-SLEEPER MOULDS) METHOD
- INDIVIDUAL MOULD METHOD
- POST-TENSIONED SLEEPERS
- TEST FOR ACCEPTANCE OF SLEEPERS
- FOR THE PRODUCTION OF THE FIRST 10,000 SLEEPERS:
- MANUFACTURING PROCESS
- TESTING ARRANGEMENT FOR STATIC BENING STRENGTH TEST FORPRESTRESSED MONOBLOCK CONCRETE SLEEPERS FOR BG AND MG
- TABLE - 1
- TABLE - 2
- PROPERTIES OF CONCRETE:
- DETAILED PROCESS OF PRESTRESSED RAILWAY CONCRETE SLEEPERS
- PROCESS FLOW DIAGRAM
- SUPPLIERS OF RAW MATERIALS
- PORTLAND CEMENT
- STEEL WIRE (HIGH TENSILE)
- SUPPLIERS OF PLANT & MACHINERY (GLOBAL)
- SUPPLIERS OF PLANT & MACHINERY
- PROJECT ECONOMICS
- SYSTEMS
- BASIS FOR RAW MATERIAL COMPUTATIONS
APPENDIX – A:
01. PLANT ECONOMICS
02. LAND & BUILDING
03. PLANT AND MACHINERY
04. OTHER FIXED ASSESTS
05. FIXED CAPITAL
06. RAW MATERIAL
07. SALARY AND WAGES
08. UTILITIES AND OVERHEADS
09. TOTAL WORKING CAPITAL
10. TOTAL CAPITAL INVESTMENT
11. COST OF PRODUCTION
12. TURN OVER/ANNUM
13. BREAK EVEN POINT
14. RESOURCES FOR FINANCE
15. INSTALMENT PAYABLE IN 5 YEARS
16. DEPRECIATION CHART FOR 5 YEARS
17. PROFIT ANALYSIS FOR 5 YEARS
18. PROJECTED BALANCE SHEET FOR (5 YEARS)
