What is a CMU lintel block?
CMU lintel block performs a similar function to bond beam blocks as a key structural component for many buildings. Lintel blocks combine to create lintel beams. These beams support the structure by transferring loads from above the beam to the walls on either side of the opening. They are also prefabricated and made with pre-stressed concrete.
What are the different types of lintels for concrete masonry construction?
Because of their rigidity, strength, durability, fire resistance and aesthetics, the most common types of lintels for concrete masonry construction are those manufactured of precast reinforced concrete or reinforced concrete masonry units (ref. 3).
What is precast concrete lintel system?
The precast concrete lintel system is a unique and versatile building assembly system that is easily constructed with a minimum of material and labor. It employs prefabricated ready-mix concrete blocks in the form of lintels, wedge beams, and deck slabs.
What is a lintel?
A lintel is one type of beam which used to support the above wall when openings like doors, windows etc. are necessary to provide a building structure.
What does CMU mean in masonry?
Concrete Masonry UnitsConcrete blocks, also known as Concrete Masonry Units or CMUs, provide very durable structural and non-structural partitions. They are generally used as a backup wall that gets covered with a finish material or exposed in utilitarian spaces like mechanical rooms or basements.
What is a block lintel?
Lintel blocks are U-shaped horizontal masonry units which are placed above the openings. blocks are arranged in a course such that lintel beam can be formed. Lintel beam the wall portion which is above the opening or between two vertical supports.
What are CMU used for?
A concrete masonry unit (CMU) is a standard-size rectangular block used in building construction. CMUs are some of the most versatile building products available because of the wide variety of appearances that can be achieved using them.
What is the difference between CMU and concrete?
Poured concrete walls have better lateral strength than CMU block foundations, which improves their resistance to pressure from water and soil. A poured wall doesn't have joints like a block wall, so it is easier to waterproof.
What is a concrete block lintel?
Lintel or channel blocks are U-shaped concrete masonry units used above openings to create lintels. Since lintel block units are solid along the bottom, the underside can be exposed at openings. However, because of this feature, these block units do not allow vertical reinforcement to extend through them.
What are the two types of lintel?
The main types of lintels are: Brick lintel, timber lintel, steel lintel and concrete lintel.
Is CMU the same as masonry?
Concrete block is made from Portland Cement, aggregates and water. It is also known as a concrete masonry unit (CMU). As a building material, concrete offers several attractive characteristics to designers and builders, including the following: Durable.
Is CMU load bearing wall?
The CMU walls act as load-bearing walls which are widely used in the construction of residential as well as commercial buildings. The concrete masonry unit has a rectangular shape. The concrete masonry units have an interlocking system that gets fitted into each other.
How strong is CMU?
Cmu compressive strength is the psi calculated from the net area of the individual unit. The minimum average net compressive strength per ASTM C90, as of the 2014 edition, is 2000 net psi. Previous editions of C90 indicated 1900 net psi.
How long do CMU foundations last?
How long does a concrete foundation last? If the contractor does the job right, a concrete foundation should have a life expectancy of more than 150 years. Naturally, homes built with quality materials and a good finish will last longer than those that are poorly constructed to begin with.
What does CMU mean?
"Cracks Me Up" is the most common definition for CMU on Snapchat, WhatsApp, Facebook, Twitter, Instagram, and TikTok. CMU. Definition: Cracks Me Up.
Why do CMU have holes?
So why do they have a hole? The one reason they are there is to make the blocks lighter and easier for a mason to handle. Also, the primary purpose of the cells is that they align from top to bottom of the wall when laid, and enable a builder to fill some cells with grout/concrete in order to strengthen the wall.
What is the difference between a beam and a lintel?
The beam carries the load from slab and transfers it to the column from, column it is transferred to the footing and from footing finally to the soil. Whereas lintel carries the load of the wall above the openings and transfers it to walls only.
Are Box lintels load-bearing?
SOLID WALL BOX LINTELS The lintel is designed to carry the full load of wet masonry as soon as it is installed but must have a minimum end bearing of 150mm each side of the opening and be bedded on mortar with all perpendicular joints filled with mortar.
What is lintel in simple words?
A lintel or lintol is a type of beam (a horizontal structural element) that spans openings such as portals, doors, windows and fireplaces. It can be a decorative architectural element, or a combined ornamented structural item.
Are Box lintels stronger than steel?
As mentioned above, steel lintels are stronger as they are able to carry more weight, but there are other variants of concrete lintels as well that can be compared to the strength of a steel one.
INTRODUCTION
Lintels and beams are horizontal structural members designed to carry loads above openings. Although lintels may be constructed of grouted and reinforced concrete masonry units, precast or cast-in-place concrete, or structural steel, this TEK addresses reinforced concrete masonry lintels only.
DESIGN TABLES
Tables 3 and 4 present allowable shear and moment, respectively, for various concrete masonry lintels, with vari- ous amounts of reinforcement and bottom cover based on a specified compressive strength of masonry, f’m = 1,500 psi (10.3 MPa) and the allowable stress design provisions of the 2011 MSJC (ref. 2a) and the 2012 IBC (ref.1a).
DESIGN EXAMPLE
Check for Arching Action. Determine the height of masonry required for arching action. Assuming the lintel has at least 4 in. (102 mm) bearing on each end, the effective span is:
NOTATIONS
b = width of lintel, in. (mm) Dlintel = lintel dead load, lb/ft (kN/m) Dwall = wall dead load, lb/ft (kN/m) d = distance from extreme compression fiber to centroid of tension reinforcement, in.
What is a CMU Block?
A CMU block is an environmentally friendly building material made from:
Uses for CMU Blocks
CMU construction has its perks and drawbacks depending on the type of walls that need to be erected.
CMU Surface Finishes
CMUs are large, concrete blocks, so they’re not the most aesthetically pleasing building material. You can, at a premium cost, find suppliers that will offer an array of finishes for concrete masonry units. The most common finishes are:
1. Timber Lintel
In olden days of construction, Timber lintels were mostly used. But now a days they are replaced by several modern techniques, however in hilly areas these are using. The main disadvantages with timber are more cost and less durable and vulnerable to fire.
2. Stone Lintel
These are the most common type, especially where stone is abundantly available. The thickness of these are most important factor of its design. These are also provided over the openings in brick walls. Stone lintel is provided in the form of either one single piece or more than one piece.
3. Brick Lintel
These are used when the opening is less than 1m and lesser loads are acting. Its depth varies from 10 cm to 20 cm, depending up on the span. Bricks with frogs are more suitable than normal bricks because frogs when filled with mortar gives more shear resistance of end joints which is known as joggled brick lintel.
4. Reinforced Brick Lintel
These are used when loads are heavy and span is greater than 1m. The depth of reinforced brick lintel should be equal to 10 cm or 15 cm or multiple of 10 cm. the bricks are so arranged that 2 to 3 cm wide space is left length wise between adjacent bricks for the insertion of mild steel bars as reinforcement.
5. Steel Lintel
These are used when the superimposed loads are heavy and openings are large. These consist of channel sections or rolled steel joists. We can use one single section or in combinations depending up on the requirement.
6. Reinforced Cement Concrete Lintel
At present, the lintel made of reinforced concrete are widely used to span the openings for doors, windows, etc. in a structure because of their strength, rigidity, fire resistance, economy and ease in construction. These are suitable for all the loads and for any span.
INTRODUCTION
Lintels function as beams to support the wall weight and other loads over an opening, and to transfer these loads to the adjacent masonry.
LINTEL DIMENSIONS
Precast lintel dimensions are illustrated in Figure 1. Precast concrete lintels are manufactured to modular sizes, having specified dimensions corresponding to the concrete masonry units being used in the construction.
LINTEL DESIGN
Precast concrete lintels are designed using the strength design provisions of Building Code Requirements for Structural Concrete, ACI 318-99 (ref. 2). In strength design, service loads are increased to account for variations in anticipated loads, becoming factored loads. The lintel is then sized to provide sufficient design strength.
DESIGN EXAMPLE
The residential basement wall shown in Figure 3 needs a lintel over the window opening. The floor live load is 400 lb (1.8 kN) per joist and the floor dead load is 100 lb (0.44 kN) per joist. Consider the floor joist loads, spaced at 16 in. (406 mm) on center, as uniformly distributed.
NOTATIONS
a = depth of equivalent rectangular stress block, in. (mm) As = area of tension reinforcement, in.² (mm²) b = actual width of lintel, in. (mm) c = distance from extreme compression fiber to neutral axis, in.
Bond Beam Block
Due to their design, standard CMUs don’t offer any way of linking together the horizontal support within a structure. Their sides are enclosed, with open sections in the middle for adding vertical reinforcement, but not offering any link to their horizontal neighbors.
Lintel Block
CMU lintel block performs a similar function to bond beam blocks as a key structural component for many buildings. Lintel blocks combine to create lintel beams. These beams support the structure by transferring loads from above the beam to the walls on either side of the opening. They are also prefabricated and made with pre-stressed concrete.
Controlling Grout Flow in Bond Beams
When constructing a wall with bond beams or lintel blocks, grout is usually used to fill the blocks and hold the reinforcement in place. In lintel blocks, the bottom is closed, so grout stays in place without any extra effort. Bond beam blocks, on the other hand, are open, so any grout poured into a block will flow down into the cells below it.
Locate a Dealer for Your CMU Block Needs
When it comes to choosing the right CMU blocks for your project, you’ll need to know the differences between bond beam blocks and lintel blocks. Bond beam blocks are typically used in the course of a wall, while lintels go over an opening, like a door or a window.
What are Lintels?
A lintel is an element of construction used to span or bridge a gap between two structural supports (commonly vertical columns).
Precast Concrete Lintels Width
Very often, the width of the lintel depends on the structure where it will be installed. For example, a beam that is several parts wide would require a bigger lintel compared to beams that are in one piece.
Precast Concrete Lintels Thickness
The thickness of the lintel also differs depending on what they are going to be used for and their installation requirements.
Precast Concrete Lintels System
The precast concrete lintel system is a unique and versatile building assembly system that is easily constructed with a minimum of material and labor.
Precast Concrete FAQs
a) Precast concrete lintels can be used to span up to 40m between columns, without intermediate beams.
Different Types of Lintels
There are different types of Lintels used in construction. The different types include:
Lintels FAQs
Reinforced concrete lintels are one of the most common types of lintels found in the construction industry around the world.
Self-Weight or Dead Load of Masonry Lintel
All solid masonry and concrete lintels must be adequately grouted. The dead load of the lintel can be computed if enough information about the dimension of the lintel is available. For design purposes, initial or preliminary cross-sectional dimensions for the lintel are considered.
Dead Load of the Wall Above the Lintel
The dead load masonry above the lintel is the weight of masonry contained in a forty-five-degree triangular area above the lintel if arching action is considered to occur. Consequently, the dead load for which the masonry lintel must be designed consists of masonry dead load in the triangular area plus self-weight of masonry lintel.
Dead load and live load transferred from the roof or the floor supported by the wall over the opening
Live and dead Loads exerted on masonry lintel by roof or floors could be either concentrated or uniform loads. Regarding concentrated loads, depending on the results of tests, a method for specifying concentrated load distribution on walls is suggested by NCMA.
