Construction Guide for Masonry Buildings with Appropriate Technologies, Summaries of Structural Design and Architecture

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UNIVERSIDAD NACIONAL DE INGENIERIA

STRUCTURAL LABORATORY FULL SCALE TESTING DIVISION CISMID

MASONRY CONSTRUCTION GUIDE

March, 2004 Lima - Perú

Construction of Masonry Buildings with appropriated technologies

CONSTRUCTION OF MASONRY BUILDINGS WITH

APPROPRIATED TECHNOLOGIES

Japanese Advisor Committee

Yokohama National University Dr. Yutaka Yamasaki

Center for Better Living Tsukuba Building Test Laboratory Dr. Mikio Futaki

Ministry of Land Infrastructure and Transport National Institute for Land, Infrastructure and Management Mr. Takashi Kaminosono Mr. Tetsuro Goto

Building Research Institute Mr. Hiroto Kato Dr. Koichi Kusunoki

Infrastructure Development Institute Mr. Ryokichi Ebizuka Mr. Satoshi Nomura

Peruvian Researchers Committee

Faculty of Civil Engineering Staff (CISMID/FIC/UNI)

Dr. Carlos Zavala Eng. Patricia Gibu Eng. Claudia Honma Eng. Oscar Anicama Eng. Jorge Gallardo Eng. Leslie Chang Bach. Eng. Guillermo Huaco Mr. German Bautista Mr. Larry Cardenas

Construction of Masonry Buildings with appropriated technologies

INITIAL REMARK

Masonry houses with good structural performance may be constructed by appropriate construction procedures, good structural detailing and good quality control. This guide has been divided in fourteen sections following the construction procedure. Structural detailing and quality control are discussed between the Japanese Advisor Committee and CISMID considering the Peruvian construction system and the Japanese concept on structural detailing, such as anchorages of reinforcements, and quality control. This guide should be used for two or single story house, because our experiment was performed with a real size 2 story house.

Each section presents questions of how to execute the construction works and also recommendations to assure the quality in the construction site. When an item is very important signal with a small man appear and shows the recommendation in green color. Also if crucial note appear, a signal of stop will appear showing in red color the recommendation. These kinds of recommendations must be follows if the quality wants to be reach on the construction site.

We hope you enjoy the reading of this guide and also spread the knowledge and recommendations among your colleagues. It will help to improve our construction technology on masonry houses.

Construction of Masonry Buildings with appropriated technologies

CONTENTS

THE CONSTRUCTION OF A MASONRY HOUSE

1. Introduction ---------------------------------------------------------------------------------------- 1
2. Which materials we use? ----------------------------------------------------------------------- 1 zCement zSand (fine aggregates: fine and thick sand) zCrushed Stone (thick aggregates) zSand & Gravel (natural mix of aggregates) zWater zMasonry units zSteel Reinforcement zWood
3. Which elements are the parts of the structural system? --------------------------------- 3
4. Where are these elements and materials in a real house? ----------------------------- 4
5. How do you know if walls amount is enough? --------------------------------------------- 5 zExample of how to check wall density
6. What should I do before starting the construction? --------------------------------------- 9 zPreparing the ground zDrawing the structure on the ground
7. How should I build the foundation? ---------------------------------------------------------- 10 zSite conditions zDigging of trench zPrepare bottom of foundation zPlace the reinforcement of the columns for walls zPlace the simple concrete in the foundation zDetail example of foundation
8. How to build the over footing? ----------------------------------------------------------------- 12
9. How to build a wall? ----------------------------------------------------------------------------- 12 zPreparation of the bricks zPreparation of the mortar zThe construction process zAdditional Notes
10. How to set the confining columns to the wall? ------------------------------------------- 15 zPlacing the forms zPlacing of concrete
11. How to tie the walls and Columns? -------------------------------------------------------- 16
12. How to build the slab and beams? --------------------------------------------------------- 17 zPreparing the concrete for beams and slab zPlacing the concrete on beams and slab
13. How to finish the surface of the elements? ----------------------------------------------- 21
14. How to control the quality of materials? --------------------------------------------------- 22 zObtain samples of fresh concrete? zSlump zQuality control of masonry

GLOSSARY ---------------------------------------------------------------------------------------------- 24 zBasic Concepts zMaterials zTools and Equipment

Construction of Masonry Buildings with appropriated technologies

zSand & Gravel (natural mix of aggregates) Sand & Gravel is a natural mix of stone of different sizes and thick sand. It is used to prepare concrete of low resistance or quality like run foundation, over-footing, false floor.

zWater Water shouldn’t contain filthy elements, should be clean, drinkable and fresh.

Do not use dirty water

zMasonry units They are clay bricks and lime-siliceous bricks. Masonry units can be solid, hollow or tubular. To consider solid section without holes must more than 75% of the geometrical area. The minimum compression stress of bricks is 50 kgf/cm 2.

Do not use uncooked clay bricks or irregular bricks. Clay bricks which are so white must not be used.

zSteel Reinforcement For confined reinforced concrete elements corrugated bars of 9.15m length and diameters of 3/8” and 1/2” should be used. For stirrups or hoops can be used flat bars of 1/4” diameter. For tying reinforcement bars black wire n{16 is used. To prevent oxidation storage of bars can be cover by plastic sheets of wood boards.

zWood Wood boards and braces are used as form (mold). Forms should be dry and protected from water; otherwise it remains humid (wet), swells up and becomes soft. It is used to apply a cover of oil (petroleum) in the surface of wood board before its use as a form.

Construction of Masonry Buildings with appropriated technologies

Vertical (head) joint

Horizontal (head) joint

Masonry

panel

Unreinforced

concrete beam

G.L. Foundation

Castellated

vertical

edge

Clay brick

unit

Mortar

Stirrup

Reinforcement

of RC frame

vertical

member

If soil conditions are not good,

like soft sand or flexible soil,

the over footing must have

minimum steel reinforcement.

Lintel

Light weight

clay brick

RC one-way

small beam

RC slab

Reinforcement

of RC frame

horizontal member

3. Which elements are part of the structural system?

Construction of Masonry Buildings with appropriated technologies

Block in Material Wall L (m) L(cm) t (cm) e (cm) h (m) h(cm) Awall(m2) Side Masonry AB1 1.50 150.00 15.00 13.00 2.50 250.00 0. Side Masonry B'C1 0.50 50.00 15.00 13.00 2.50 250.00 0. width Masonry AB2 2.50 250.00 25.00 23.00 2.50 250.00 0. Side Masonry AA'3 0.70 70.00 15.00 13.00 2.50 250.00 0. side Masonry CD'1 2.70 270.00 15.00 13.00 2.50 250.00 0. side Masonry DD'3 0.80 80.00 15.00 13.00 2.50 250.00 0. side Masonry D'E3 0.80 80.00 15.00 13.00 2.50 250.00 0. width Masonry D'E2 1.20 120.00 25.00 23.00 2.50 250.00 0. 㺌Awall= 1.76 m Ahouse(m2)= 51.00 m

Wall Density= 3.5% 㻠 4.0% Fail

If wall density is less than the minimum required, wall density can be increase increasing the thickness of the wall or increasing stiffness replacing a masonry wall by a concrete wall.

5. How do you know if walls amount is enough?

Structural design project is necessary to compute the reinforce elements, confinement elements, walls amount, footings and others. A preliminary computation usually used in the design phase of the project is the procedure known as wall density ratio. This procedure is very simple and consists in finding the ratio between walls area and story area. The ratio should be examined on each floor. It should also be examined severally in the vertical direction and in the horizontal direction. A wall whose length is under 30 cm. shouldn’t be counted because it isn’t effective enough. As a result value the ratio must be compare with a threshold value proposed by the Peruvian committee of masonry standards, which are as follows:

Here the minimum wall density ratio is presented as a percent and is given for each soil type and each earthquake zone in Peru.

z Example of how to check wall density As an example we will consider the two story masonry house experimented in CISMID/FIC/UNI, during this project. In the Figure on the next page the plan of each story is presented. We will developed the first story wall density requirement as example.

a) Check in the vertical direction on the 1st^ floor Each wall is named with two nearest horizontal axis and is own vertical axis. Then each wall is identified its length, which is length of the wall including confined columns and the effective thickness of the wall (without finishing). We already know the area of the story is 51 m2, and the results of the computations are presented in the following table:

From the results in the vertical direction we found a wall density ratio of 3.5% which is not enough for our requirement in zone 3 with soil type 2, who need a minimum of 4% ratio. For this reason, if we build it in zone 3 with soil type 2, we need to increase the amount of walls in this direction or we need to replace one of the walls by a concrete shear wall.

Soil Type Zone-3 Zone-2 Zone- S1 4% 3% 1% S2 4% 3% 2% S3 5% 4% 2%

Construction of Masonry Buildings with appropriated technologies

φHorizontal directionψ

1 st^ floor

2nd floor

䎇 Vertical direvtion

(^) 䎉

t = wall thickness e = effective thickness h = height of wall L = length of wall

Construction of Masonry Buildings with appropriated technologies

Block in Material Wall L (m) L(cm) t (cm) e (cm) h (m) h(cm) Awall(m2) Side Masonry AB1 1.50 150.00 15.00 13.00 5.00 500.00 0. Side Masonry B'C1 0.50 50.00 15.00 13.00 5.00 500.00 0. width Masonry AB2 2.50 250.00 25.00 23.00 5.00 500.00 0. Side Masonry AA'3 0.70 70.00 15.00 13.00 5.00 500.00 0. side Masonry CD'1 2.70 270.00 15.00 13.00 5.00 500.00 0. side Masonry DD'3 0.80 80.00 15.00 13.00 5.00 500.00 0. side Masonry D'E3 0.80 80.00 15.00 13.00 5.00 500.00 0. width Concrete D'E2 1.20 120.00 25.00 212.38 5.00 500.00 2. 㺌Awall= 4.03 m Ec= 217000 kg/cm2 Ahouse(m2)= 51.00 m Em= 23500 kg/cm Wall Density= 7.9% 㻠 4.0% OK

Block in Material Wall L (m) L(cm) t (cm) e (cm) h (m) h(cm) Awall(m2) Side Masonry 12A 2.35 235.00 15.00 13.00 5.00 500.00 0. Side Masonry 23A 3.45 345.00 15.00 13.00 5.00 500.00 0. Side Masonry 12C 2.35 235.00 15.00 13.00 5.00 500.00 0. Side Masonry 2'3C 2.30 230.00 15.00 13.00 5.00 500.00 0. Side Masonry 2'3D 2.30 230.00 15.00 13.00 5.00 500.00 0. Side Masonry 11'D' 0.93 93.00 15.00 13.00 5.00 500.00 0. Side Masonry 1'2D' 0.93 93.00 15.00 13.00 5.00 500.00 0. Side Masonry 23E 3.45 345.00 15.00 13.00 5.00 500.00 0. 㺌Awall= 2.35 m Ahouse(m2)= 51.00 m

Wall Density= 4.6% 㻠 4.0% OK

d) Check in the vertical direction on the on the 2nd^ floor In order to find the wall density ratio for this direction, we must consider the walls who came from the lower level. It means, only the walls who start on the foundation are consider for this computation. Therefore, amount of walls for this direction is the same as the one on the first floor because wall BC3 is not consider. Then, if replacement of wall D’E2 remains on the second floor, wall density is computed in the following table:

e) Check in the horizontal direction on the on the 2nd^ floor In this direction wall 12D’ has an opening, and is divide into two: wall 11’D’ (before the opening) and 1’2D’ (after the wall). Therefore for this direction wall density become:

Then, wall density shows a reduction in this direction but is enough to satisfied the required minimum of 4%

Construction of Masonry Buildings with appropriated technologies

6. What should I do before starting the construction?

z Preparing the ground

Ground should be clean, without rubbish neither organic material nor any odd element to the ground.

z Drawing the structure on the ground

Ropes (cord) are tightened, using trestles made by wood poles nailed to a transversal stick and embedded to the ground, as shown in the figure. Trestles are placed at external part of build. Check the angle of 90{ at the corners making triangle of 3-4-5 length sides, as shown here.

Level of the ground should be verified to know how are the unevenness. It can be used level, theodolite or transparent hose level. Trace of building axis and wall alignment or laying out should be made using gypsum powder, chalk, or similar, marking the trenches for foundation.

Trestles

Wall alignment

90 { angle Laying out

Construction of Masonry Buildings with appropriated technologies

z Place the simple concrete in the foundation

With reinforcement of all columns placed and provisionally fixed, continuous foundation is filled with simple concrete. For foundation the mix of simple concrete contains a cement-(sand-gravel) ratio of 1:10 plus 30% of big stones. For the over footing the cement-(sand-gravel) ratio for the mix is 1:8 plus 30% of medium stones.

z Detail example of foundation

The upper Figure shows examples for good soil condition of likely used types of foundation: Section A-A: 0.50x0.70m foundation for 15-cm thickness wall. Section B-B: 0.60x0.70m foundation for confined column on 25-cm thickness wall. Section C-C: 0.60x1.10m foundation for staircase. When soil condition is not good, increase of width or depth of the foundation is required.

Care should be taken when transporting fresh concrete from mixer discharge to the trench, and also in placing concrete in order to not separate stones from fresh concrete. A good curing should be performed, allowing the concrete to reach enough strength, imperme-ability and durability. Lack of curing causes low resistance and it could appear cracks due to the contraction for drying of concrete.

Construction of Masonry Buildings with appropriated technologies

8. How to build the over footing?

Over the run foundation continues the over-footing to be used as support for the wall. The main purpose is to isolate the wall from the soil and provides protection against humidity. Here it is used wood boards as a form or mold the over footing.

If soil conditions are not good, like soft sand or flexible soil, the over footing must have minimum steel reinforcement to work as a foundation connection beam.

It is recommended to use a mixture ratio of cement, sand and gravel for the over footing of 1:8 plus 30% of medium stones. Also vibrator or rods are required to reach a good mixture.

9. How to build a wall?

To build the wall we must prepare the mortar and prepare the bricks before start the process. Above the over-footing, it starts layering of brick units over mortar bed, forming masonry walls.

z Preparation of the bricks Bricks should be wet before layer them so they don’t absorb water from mortar and obtaining a good adherence mortar-brick

z Preparation of the mortar To make the mortar, the mix will have thick sand - cement ratio of 5:1. Sand and cement should be mixed dry, out from the tray. Next this dry mix is put in the tray mixing it with water.

Construction of Masonry Buildings with appropriated technologies

Longitudinal layering

Transversal layering

z Additional Notes

For the next layers this procedure is repeated. It is important the thick of mortar layer, if excceds1.5cm, resistant of resulting wall will be lower. To cut a brick unit, it is used the small pick (“picota”). The pointed edge is used to mark and the opposite side is used to cut and clean the lateral surface of brick. Up to 1.50m high, worker can be stand and making the placing of bricks. Higher than this, it should be used scaffold where place materials and tools. .

Considering as example handmade bricks with dimensions of 14x24x9, the bricks can be layered longitudinally (wall thick of 14cm), or layered transversally (thick of wall is 24cm).

When bricks are hand-made, there are variability in its size, obtaining a non uniform wall thick. Wall shouldn’t be picked or broken to make pipe installation inside. It should be left needed space to contain water, drainage, or electric piping. It means that in the place projected to cross a pipe, it should be left a space without brick, place the pipe and then the space will be filled with concrete. Piping should always run vertically, never diagonally.

The ratio between the product of wall length by its thickness in reinforced walls and the area of the floor is named wall density ratio. For Housing on flexible soil wall density ratio must be at least 5%. Under good soil condition wall density must be at least 3.5 %.

Construction of Masonry Buildings with appropriated technologies

10. How to set the confining columns to the wall?

Be sure the reinforcement bars of the columns and stirrups were placed and fixed properly at the stage of the foundation. Maximum distance between confining columns in a 14cm thick wall is 3.50m and for a 24cm thick wall is 5.00m. In both sides of a wall an empty place for column place when layering bricks edges of wall are “teething” (castled vertical edge) making layers not aligned vertically at the edges of wall -as shown in photo -, and obtaining a better tying or anchorage between column and wall.

z Placing the forms The forms are made from wood panels or steel plates. Bracing of the panels is needed to assure stability of the form.

z Placing of concrete The concrete must be transport by the operator in clean cans and drop from the top of the column. The process must continue in order to assure uniformity of the mix and avoid dry joints among it. Vibration of the poured mix is required. When placing concrete a good vibration should be perform (through the use of vibrator devices if possible) in order to get a continuous element without air pockets (vacuum bags), which weakens wall resistance. For concrete with strength resistance of 210kgf/cm^2 , the volume proportioning of materials is 1 of cement, 2 of stone and 2 of sand. The water cement ratio is around 0.45. Amount of water can be varied based on the test mixing because weather conditions, temperature and other external factors.