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Chapter 1 Design of Structure

1.1 Design Methodology

DO YOUR OWN

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START

Geometric Modelling

Determination of base demand for

water

Input Collected data to EPANET

Preparation of Design &

Analysis for Specific Facilities

Preparation of Cost Estimate

END

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Figure 1 Design Process

1.2 Geometric Modeling

Figure 2: Geometric Modelling with backdrop map

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4.3 Design for Water Distribution

Below shows the schematic design steps on water distribution of both the loop and branch system.

From gathering all the necessary data up to the final distribution to be adapted, the designers chose

the most economical design in terms of the constraints stated earlier.

Figure 1-3. Water Distribution System Design Process

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4.3.2. Design of water distribution system using loop and branch system (elevated storage tank)

Loop system using elevated storage tank

For the design of loop system using elevated storage tank, the designer generate the system by the use of

EPANET, and simulate it considering all the needed data and parameters. All the needed results are shown

on the Appendix F section.

4.3.4 Design Flow Determination

Using the engineered software EPANET, the designers were able to come up with all the requirements for

the water demand and other required heads for a successful distribution system. By using the parameters

given like node elevations, pipe length, base demand, etc., the software calculated and analyze the system

if it meets the designed system flow and whether all the specific criteria are met. The manual calculation is

presented at the appendix E using Hardy Cross Method

Steps in Computation for design flow and pipe diameter:

(Total Demand of Barangay project within 15 years)

Projected Population (As computed in Appendix ) 14460 persons

Using Level 3: Individual House Connection for day demand per persons

(in lcpd- liters per capita per day) 100 lcpd

Step 1: Calculate all the water demand

A. Total Average Daily Demand (ADD) = Add x population

Total Average Daily Demand (ADD) = 14460 x 100

Total Average Daily Demand (ADD) = 1446000 l/day

Total Average Daily Demand (ADD) = 16.73611 l/sec

B. For Maximum Daily Demand (MDD) = 1.3 * ADD

For Maximum Daily Demand (MDD) = 1.3 * 16.73611

For Maximum Daily Demand (MDD) = 21.75694 l/sec

C. For Peak Hour Demand (PHD) = 2.5 * ADD

For Peak Hour Demand (PHD) = 2.5 * 16.73611

For Peak Hour Demand (PHD) = 41.84028 l/sec

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D. For Non - Revenue water = .15 * ADD

(use 15 % of ADD) 0.15*16.73611

2.510417 l/sec

Step 2:

It is also important to calculate the needed fire figh flow

(The computation is on the Appendix)

With duration of 2hrs. 62.93 l/sec

Summing up the Maximum Daily Demand (MDD) plus

Non-revenue water, the design flow is 21.75694+2.510417

Design Flow is equal to 24.26736 l/sec

converting to cu.m/day 0.024267 cu.m/day

Step 3: Calculation for pipe diameter

Using the formula Q = A x V

where: Q = MDD + Fire demand

Q = 84.68694 l/sec

using a velocity of 3 meters:

A= π D2/4

Given Q and V, the diameter of the pipe (D)

is equal to 0.189584 m

189.5844 mm

use : 200 mm diameter pipe