A T-beam (or tee beam[1]), used in construction, is a load-bearing structure of reinforced concrete, wood or metal, with a t-shaped cross section. The top of the t-shaped cross section serves as a flange or compression member in resisting compressive stresses. The web (vertical section) of the beam below the compression flange serves to resist shear stress and to provide greater separation for the coupled forces of bending. The T-beam has a big disadvantage compared to an I-beam because it has no bottom flange with which to deal with tensile forces. One way to make a T-beam more efficient structurally is to use an inverted T-beam with a floor slab or bridge deck joining the tops of the beams. Done properly, the slab acts as the compression flange. A T-beam is a structural element able to withstand large loads by resistance in the beam or by internal reinforcements. In some respects, the T-beam dates back to the first time a human formed a bridge with a pier and a deck. After all, a T-beam is, in one sense, no more than a pillar with a horizontal bed on top, or, in the case of the inverted T-beam, on the bottom.
[3] The upright portion carrying the tension of the beam is termed a web or stem, and the horizontal part that carries the compression is termed a flange. However, the materials used have changed over the years but the basic structure is the same. T-beams structures such as highway overpasses, buildings and parking garages, have extra material added on the underside where the web joins the flange to reduce the T-beam’s vulnerability to shear stress.[4] However, when one investigates more deeply into the design of T-beams, some distinctions appear. The T-beam, though simple in design, contains multiple design elements of interest. Unlike an I-beam, a T-beam lacks a bottom flange, which carries savings in terms of materials, but at the loss of resistance to tensile forces.[5] In parking garages, however, it is obvious that this lack of a bottom flange on a T-beam actually serves as an advantage in that the stem rests on shelf making the flange the upper deck. T- beam designs come in many sizes, lengths and widths depending on what the structure is and its compression tension needs.
However, the simplicity of the T-beam is in question by some who would rightly test more than one complex structure; for example, a group of researchers tested pretension inverted T-beams with circular web openings,[6] with mixed but generally favorable results. Thus, in some cases, the extra time and effort invested in creating a more complex structure proves worthwhile. A simpler matter to consider is that of which material or materials make up the construction of T-beams. Steel T-beams manufacturing process includes: hot rolling, extrusion, plate welding and pressure fitting. A process of large rollers connecting two steel plates by pinching them together called pressure fitting is a common process for non-load bearing beams. The reality is that for most roadways and bridges today, it is more practical to bring concrete into the design as well. Most T-beam construction is not with steel or concrete alone, but rather with the composite of the two, namely, reinforced concrete.[7] Though the term could refer to any one of a number of means of reinforcement, generally, the definition is limited to concrete poured around rebar.
This shows that in considering materials available for a task, engineers need to consider the possibility that no one single material is adequate for the job; rather, combining multiple materials together may be the best solution. Thus, steel and concrete together can prove ideal. Concrete alone is brittle and thus overly subject to the shear stresses a T-beam faces where the web and flange meet. This is the reason that steel is combined with concrete in T-beams. A problem of shear stress can lead to failures of flanges detaching from webs when under load.[8] This could prove catastrophic if allowed to occur in real life; hence, the very real need to mitigate that possibility with reinforcement for concrete T-beams. In such composite structures, many questions arise as to the particulars of the design, including what the ideal distribution of concrete and steel might be: “To evaluate an objective function, a ratio of steel to concrete costs is necessary”.[9] This demonstrates that for all aspects of the design of composite T-beams, equations are made only if one has adequate information.
Still, there are aspects of design that some may not even have considered, such as the possibility of using external fabric-based reinforcement, as described by Chajes et al., who say of their tested beams, “All the beams failed in shear and those with composite reinforcement displayed excellent bond characteristics. For the beams with external reinforcement, increases in ultimate strength of 60 to 150 percent were achieved”.[4] When it comes to resistance to shear forces, external reinforcement is a valid option to consider. Thus, overall, the multiple important aspects of T-beam design impress themselves upon the student of engineering. An issue with the T-beam compared to the I-beam is the lack of the bottom flange. In addition, this makes the beam not as versatile because of the weaker side not having the flange making it have less tensile strength. Concrete beams are often poured integrally with the slab, forming a much stronger “T” – shaped beam. These beams are very efficient because the slab portion carries the compressive loads and the reinforcing bars placed at the bottom of the stem carry the tension.
A T-beam typically has a narrower stem than an ordinary rectangular beam. These stems are typically spaced from 4’-0” apart to more than 12’-0”. The slab portion above the stem is designed as a one-way slab spanning between stems. A double-T beam or double tee beam is a load-bearing structure that resemble two T-beams connected to each other. Double tees are manufactured from prestressed concrete using pretensioning beds of about 200-foot (61 m) to 500-foot (150 m) long. The strong bond of the flange (horizontal section) and the two webs (vertical members) creates a structure that is capable of withstanding high loads while having a long span. The typical sizes of double tees are up to 15 feet (4.6 m) for flange width, up to 5 feet (1.5 m) for web depth and up to 80 feet (24 m) or more for span length.Rose Ritson TrenwithGreg PlowrightSee allBullshot Garage Door ServicesTip 9. Clear the Tracks Make sure the tracks on either side of the door are free from debris and, if you are so inclined, you can use a level to check the plumb.
Any major adjustments to tracks must be done by a professional garage door technician. Contact Bullshot Garage Doors on 021956269 or bullshot.nz@xtra.co.nz if you have any garage door maintenance concerns.Bullshot Garage Door ServicesTip 8. Test the Auto-Reverse Safety Features There are possibly two mechanisms: mechanical and photocell (where installed). In order to test the mechanical feature, place a piece of wood or a brick on the ground in the path of the door. When the door coming down touches that object, it should reverse direction and go back up again. To test the second, the photoelectric system with beams at each side, close your door and just pass your leg in the door’s path. Your door should ...reverse. If your opener is more than 20 years old, it may lack this basic safety features – and so it’s time to buy a new garage door opener. Contact Bullshot Garage Doors on 021956269 or bullshot.nz@xtra.co.nz if you have any garage door maintenance concerns. See allBullshot Garage Door ServicesTip 7 Check the Cables You should never tinker with the high-tension cables that lift your door because they have enough force to injure.
But you can check their condition so you know when to hire a pro. Check for broken strands and damage near the bottom roller bracket. Bullshot Garage Door ServicesTip 6. Lubricate the Moving Parts Keeping your garage door parts greased up will add years of seamless operation to your system – and it takes just 10 minutes a year! Use white lithium grease on the opener’s chain or screw, and a spray lubricant, available from your garage door specialist, to coat the overhead springs. Bullshot Garage Door ServicesTip 5. Replace the Weatherstripping If the rubber weather seal strip on the bottom of your door is brittle or cracked, replace it right away to keep the elements out of your house. Weatherstripping is sold by the hardware and home DIY stores. Just cut to size and insert into the grooves with the wide angle of the flange inside the door. Bullshot Garage Door ServicesTip 4. Inspect and Replace the Rollers The rollers, whether steel or nylon, need to be inspected twice a year and replaced every seven years or so, and even more if you use your garage door many times a day.
Worn, chipped or cracked rollers should be replaced as soon as possible. You do this by removing and reinstalling any roller brackets that are not directly attached to the cable system. Bullshot Garage Door Services3. Test the Garage Door Balance If your garage door is not properly balanced, the garage door opener will have to work harder, and it won’t last as long. After you disconnect the opener by pulling the release handle (usually a red cord), manually move the door about halfway up. If it doesn’t stay put, the counterweight system (springs) are improperly balanced. Garage door spring adjustment is best left to the professionals Contact Bullshot Garage Doors on 021956269 or bullshot.nz@xtra.co.nz if you have any garage door maintenance concerns.Bullshot Garage Door ServicesPreventive Maintenance Tips for Garage Door Owners Your garage door is the largest moving part in your entire home, and is used multiple times per day at any hour and in all seasons. To keep your garage door operating smoothly for decades to come, it’s very important that you take the time to perform regular preventive care and maintenance.
Tip 2 Tighten up the Hardware The average garage door moves up and down more than a thousand times a year. That’s a lot of movement and vibration, which can loosen the hardware. Examine and tighten all roller brackets and bolts with a socket wrench. Look and Listen The most important preventive step you can take is to observe your garage door in action every time you use it. Is it moving smoothly or is it jerky in places? Does it operate silently or does it make grinding or scraping noises? Do both sides of the system (springs, pulleys and cables) look symmetrical? NB: Contact us on 021956269 or bullshot.nz@xtra.co.nz if you have any garage door maintenance concerns. Bullshot Garage Door Services updated their cover photo.Bullshot Garage Door Services added 10 new photos to the album Remotes.Bullshot Garage Door ServicesGarage Door Services Garage Door Repairs and Servicing Rollers & Hinges Replaced Track Alignment and Adjustment... Chain and Cable Repairs Garage Door and Gate Remotes Replacement Remotes Supplied Remotes Copied and Cloned Remotes Repaired (No Callout on Remotes Cloned in Property Managers Office) Automatic Garage Door Motors Motor Replacement Stripped Gears Replaced Motor Re Calibration (Remotes Deleted and Added) Paul Trenwith 021956269 Bullshot.nz@xtra.co.nz Prompt Efficient Auckland Wide Mobile Service Bullshot Garage Door ServicesA broken garage door is a security risk.