Thrust block design pdf

Form vertical surfaces of poured concrete thrust blocks except on bearing surface. Thrust block is usually defined as a mass concrete block design to provide resistance by transferring the thrust force to the soil through a larger surface area of the block such that the. Many engineering spreadsheets are available for use. Conservative assumptions, along with an explicit safety factor, have been employed to assure a conservative design with an adequate overall safety factor. The pipes are steel and welded and their diameters. Engineering design center standard drawings 1st edition january 2016. This etl promulgates, as well as supplements, criteria found in hqusace architectural and engineering instructions, design. Conservative assumptions, along with an explicit safety factor, have been employed to assure a conservative. The design of thrust blocks for water pipelines and sewer force mains vary from one pipe material or standard to another just like the design of pipe wall thickness. Designing thrust systems thrust restraint brochure a brochure outlining design theory and a design aid of restrained joint systems for ductile iron pipe. Rep r 128 guide to the design of thrust blocks for buried.

Standard construction details city of ormond beach, fl. Thrust restraint design for buried piping common design guidelines. On a pipeline with unrestrained flexible joints, a pipe special will normally need to be restrained using an anchor or a thrust block. Thrust block forces on pipe bends anchor due to liquid velocity and internal pressure online resulting force calculator sponsored links in a piping structure without adequately support fluid flow velocities and internal pressures may create intolerable forces and tensions.

Guidelines for the design of buried steel pipe july 2001 i acknowledgments the following people with their affiliations contributed to this report. A similar approach may be used to design bearing blocks to resist. P18 standard thrust block p19 restraint of joints for ductile iron and pvc pipe at tee connection p20 restraint of joints for ductile iron and pvc pipe at 90degree vertical or horizontal bend p21 restraint of joints for ductile iron and pvc pipe at a dead end or each side of valve p22 casing for water mains. Tees, bends, plugs, hydrants, and other appurtenances and fittings require thrust blocks to restrain the pipe. Guide to the design of thrust blocks for buried pressure. Justifying the need for a new framework for the design of thrust blocks, the white paper noted the shortcomings in current practice.

Designing thrust systems a computer program to aid in the design of restrained joint systems for ductile iron pipe. Flange glands gaskets rj pipe tie rods combined systems. In efect, the thrust block transfers the load from the pipe to a wider load bearing surface. Engineering and design revision of thrust block criteria in tm 585afm 8810, vol. In another part of appendix c, the use of full passive pressure was incorrectly used to calculate the lateral restraint for thrust blocks. Pressure pipe thrust block design utoledo engineering. Thrust control may also be needed at the end of the pipeline and at inline control valves. By restraining certain joints at bends and along the pipeline, the resultant.

T ru f where r, is the ultimate ground resistance, and f is the force applied to the thrust block. Right now im just using the passive pressure on the face of the block, but apparently a large component of the resisting force is generated by the passive pressure and frictional resistance on the pipe. I am trying to design a thrust block for a 450mm diameter water main but its turning out to be very big as its in sandy clay soil. Thickness design of ductile iron pipe hydraulic analysis of ductile iron pipe thrust restraint design for ductile iron pipe design of ductile iron pipe on supports awwa standards ansiawwa c104a21. Fairfax water standard details table of contents drawing no. Title 1 1 service connection with 58 or 34 meter 1a 1 service connection with 1 meter.

An improved approach for the design of thrust blocks in. Apr 26, 2015 the thrust reduction factor, tryis defined as. Pressure pipe thrust block design f tee t 2pasin e2 bend ab t x sfsb ab bearing area of thrust block sq. Design of thrust block free download as excel spreadsheet. A design guide for thrust blocks to restrain the forces generated by changes in direction of fluid flow in jointed buried pressure pipeline networks. A step by step design approach is detailed, principally for thrusts up to 1,000kn, limiting the pressure range, pipe diameter and the thrust block sizes.

The parameters involved in the design include pipe size, design pressure, angle of the bend or configuration of the fitting involved, and the horizontal bearing strength of the soil. Forces causing thrust static forces internal pressures dynamic forces. Any time you ask them for a horizontal bearing pressure to use in your thrust block design, they put so many factors of safety on it you end up designing your block for a soil with the consistency of custard. Calculate the effective weight determine minimum thrust block size to suit pipe and excavation dimensions. The calculation of the thrust force for pipeline installation using the direct pipe method. Abrupt changes in pipeline grade, horizontal alignment, or reduction in pipe size normally require anchors or thrust blocks to absorb any axial thrust of the pipeline. Rslcos 2 restrained length dependant upon pipe size type of fitting internal pressure depth of cover. This report presents a stepbystep design guide for thrust blocks to restrain the forces generated by changes in direction of fluid flow in jointed buried pressure pipeline networks.

In an effort to protect public health during the evolving coronavirus outbreak and to ensure safe, clean water continues to flow to customers homes, wssc water will suspend all water service shutoffs. Concrete thrust block design for pipe angles, tee, wye, and dead end per. Jan 22, 20 one last rant is about geotechnical engineers. Thrust block for pipelines case study of water supply. There is also a horizontal component of thrust t x in vertical bends. It provides a background knowledge to the underlying principles and theory involved with designing thrust blocks for buried pipelines. This program is based on the equations and procedures found in the dipra brochure thrust restraint design for ductile iron pipe. Design of thrust blocks consists of determining the appropriate bearing area of the block for a particular set of conditions. The designer should verify that the design complies with nrcs standards and that the standard applies to the site. Where a b is the required bearing area of the thrust block, s f is the safety factor, t is the.

Block height h should be chosen such that the calculated block width b varies between one and two times the height. Thrust blocking prevents main line from moving when the pressure load is applied. Jul 05, 2018 the calculator the tool below is an early part of a larger effort to determine the thrust block detailing. Although seldom used today we include this information on thrust blocking design as one of several proven methods of resisting thrust in varying soil conditions. Pnws awwa spring conference may 6th 2016 doug schlepp, pe. With approximately 50,000 members, awwa provides solutions to improve public health, protect the environment, strengthen the economy and enhance our quality of life. This 103page book gives stepbystep design guidance on how thrust blocks up to kn are used to restrain the forces generated by changes in direction of fluid flow in jointed buried pressure pipeline networks. The designer must understand the assumptions and calculations contained in the spreadsheets and is responsible for their use. This creates tremendous confusion among consulting engineers and owners of projects.

Thrust restraint design for ductile iron pipe design of ductile iron pipe on supports awwa standards ansiawwa c104a21. Thrust block design free download as excel spreadsheet. For thrust vertically upward see figures c and c14, and for thrust vertically downward see figure c15. The design of the rcc thrust block has been done manually. The size of thrust block for downward directed thrust is calculated by. In design of thrust blocks, nfpa 2402 calls out the thrust equation under figure a. Thrust force on the pipe bend allowable soil bearing pressure to the depth to the center of the thrust block is area of thrust block required a min. Thrust blocks are required where fittings are used to change the direction i. I want to design some thrust block for horizontal buried water pipelines at their bends. Thrustblock excel spreadsheet calculators engineers edge. A tb bottom area of thrust block, t y vertical component of thrust force, q s allowable bearing capacity of soil, and f s factor of safety. Using the tables on the following page you can calculate the size of the thrust block for various pipe sizes. Therefore, the area behind the thrust block must engage enough soil area to resist the resultant thrust force at a change in direction.

This document has been developed by the unibell pvc pipe association for design and installation of gasketed pvc fittings where gasketed pvc pressure pipe is used in potable water, force main, pressure irrigation, and. Thrust block bearing design size varies with pipe size, soil and pressure transfers thrust to bearing area soil bearing strength s b. The calculator the tool below is an early part of a larger effort to determine the thrust block detailing. The purpose of this etl is to provide design engineers with criteria that will be used in preparing designs and project specifications for construction of thrust blocks for underground water and wastewater piping at facilities for the army and air force. Thrust block bearing design size varies with pipe size, soil and pressure transfers thrust to bearing area soil bearing strength s b lb. The size of the thrust block depends on the water pressure in th epipe, size of the pipe, type of fitting, and soil bearing. The required bearing block area is then, for a horizontal bend, where sf is a safety factor usually 1. The thrust block design is commonly determined by the equation a b s f ts b.

The purpose of this etl is to provide design engineers with criteria that will be used in preparing designs and project specifications for construction of. Guidelines for the design of buried steel pipe july 2001. Thrust restraint design for ductile iron pipe dipra. Thrust block design structural engineering general. Thrust restraint design for buried piping common design guidelines 2008 c27. The guidance given in this report is principally for thrusts up to. Thrust blocks for horizontal bends are shown in figures c9, c10, c1l and c12. Determining size and type of thrust blocking size and type of the thrust block depends on maximum. The thrust force is required to push the pipeline into the borehole and was investigated by. By restraining certain joints at bends and along the pipeline, the resultant thrust force is transferred to the surrounding soil by the.

Analysis of this aspect will follow like the above section on bearing blocks. Thrust blocks are used at these locations toprevent damage to the pipe caused by unsupported pipe movement. Introduction berinag is a hill station in pithoragarh district, which. Thrust blocks for vertical bends are shown as follows. City hall 22 south beach street ormond beach, fl 32174 phone. Timken offers a range of radial, thrust and angular contact ball bearings in both metric and inch sizes. Pdf design of thrust block for water and waste water industry in nigeria is based on traditional approach by ductile iron pipe research. In the coming weeks, i would like to add block height, width, volume and visualizations to detail the parameters. Guide for pvc pressure fittings unibell pvc pipe association. T resultant hydrostatic pressure lbs sf safety factor 1. The thrust block should be designed knowing the intensity of the thrusts developed in the pipe and the load bearing strength of the soil.

The pipe will be buried under 4 feet of soil and include 90 degree bends. Pressure pipe thrust block design college of engineering. How can i design thrust block for steel water pipelines. A step by step design approach is detailed, principally for thrusts up to 1,000kn, limiting the pressure range, pipe.

Calculate thrust block size to resist downward forces at upturn bends. Where a b is the required bearing area of the thrust block, s f is the safety factor, t is the resultant thrust force see connections bulletin pd2, and s b is the bearing strength of the soil. All fittings shall be anchored by mechanical means or by concrete thrust blocks, or both, if required by the boston water and sewer commission or as noted on the contract plans. Index terms thrust restraint, momentum, thrust absorber, deviation angle. Design the thrust blocks for upper vertical bends such that the sum of the effective weight of the concrete, bend and fluid is equal to or greater than the vertical component of the design thrust force.

Housed units timken spherical roller bearing solidblock housed units process a unique caststeel design that. P18 standard thrust block p19 restraint of joints for ductile iron and pvc pipe at tee connection. Internally restrained joints external mechanical restraint devices concrete thrust blocks when internal or external restraint is used, the pipeline becomes its own thrust block. Established in 1881, the american water works association is the largest nonprofit, scientific and educational association dedicated to managing and treating water, the worlds most important resource. Thrust control may also be needed at the end of the pipeline and at inline control. While the theory used is applicable in any circumstances, the design of large scale thrust blocks requiring structural reinforcement, etc, is not covered. The guidance given in this report is principally for thrusts up to kn, limiting both the pressure range and pipe diameters and, more importantly, the thrust block sizes.