Masonry

Terms –F > 15-5 –Go thru all figures –Joints between brick = ¼ inch

Brick F 15-6 –Go thru sizes for brick –Compressive strength range 2500psi – 22,000psi – T 15-1 shows mortar strength –Brisk wall only as strong as weakest part

Brick Pattern bonds –How bricks are laid Running bond – only stretcher courses with head joints centered over stretchers Common bond – header course repeated at regular intervals – usually 5 th,6 th or 7 th course Flemish – bond – alternates stretchers and headers in each course headers are centered over stretchers English bond - alternate courses of headers and stretchers Stack – no interlocking – architectural effect –F 15-7

Hollow Masonry Walls Masonry Cavity Walls Two masonry wythes separated by a 2” minimum airspace and held together with metal ties Advantages over single masonry wall: greater resistance to moisture penetration, better thermal and acoustical insulation, excellent fire resistance –Utility wall – made from utility brick, two walls with brick used to bond walls together

Hollow Masonry Walls Reinforced Brick Masonry Walls Hollow walls are filled with grout and rebar to provide strength Can be precast Provides a strong wall with exterior finish – uses less concrete

Bond Beams and Lintels Bond Beam –Continually reinforced horizontal beam of concrete or masonry designed to provide additional strength and prevent cracking Frequently placed in foundations and at roof levels –Lintel – short beam of wood, steel, or reinforced brick masonry to span opening in masonry wall –Masonry arch –F15-11

Control Joints Expansion Joints Used to permit differential movement due to movement of floor slabs, foundation Separate walls into sections with vertical expansion joints Joints at doors and windows, columns, pilasters, wall offsets, cross walls, under shelf anglesin multistory buildings –Control Joint – cut into masonry wall to control shrinkage cracking

Control Joints Structural bonding Flexible ties extending across joint or interlocking construction F –Flashing – layers of impervious material Used above vertical joints, roof and wall junctions, window sills, other projections, chimneys F15-13

Concrete Masonry Concrete Block Concrete Tile Solid load bearing concrete block –Over 75% concrete Hollow load bearing concrete block Hollow non- load bearing concrete block –Hollow block = at least 25% of core area is empty

Concrete Masonry Either heavy weight or light weight concrete blocks –Blocks can either be laid using mortar or laid dry –If dry use parging to join block together –F 15-14

Reinforced Concrete Masonry Provides additional strength and prevents cracking F15-15, > 18

Pattern Bond Running bond most common F 15-20

Estimating Quantity Bricks –1. Calculate net surface area of wall –2. calculate surface area of 1 brick including mortar –3. divide wall area by brick area –4. multiply by number of wythes in wall –5. add an amount for waste

Estimating Quantity Mortar –Volume per brick =(t)(W)(L+H+t) –t = mortar thickness –W = brick width/depth inches –L = length of bricj inches –H = height of brick inches –Add 25% waste –For double wall must add in for mortar in space

Wind load on Fresh Masonry Need to brace fresh wall until mortar has cured –F –Safe unbraced height = (Wt of wall / unit of surface x wall thickness)/wind force –T 15-3

Mortar –Must be well mixed –Must have correct mix of fines and coarse material –Must not be used more than 2.5 hours after initial mixing

Placing Masonry and Reinforcing –CMU and brick absorb water –Should be stored dry –Should be wetted before use and allowed to surface dry –Joints must be tooled for watertight joints