What are universal beams?

Known in Australia as universal beams (UB) and universal columns (UC) but also commonly referred to as I beams and H beams, these are named after the I and H shaped appearance of their cross section.

The vertical middle section of the beam is known as the ‘web’ and the horizontal components are called ‘flanges’. These beams are designed to support a lot of weight in one direction. UBs used in floors will support more force vertically than a standard square beam, but are weaker against horizontal movement and do not react well to twisting. They are used as a component in floor framing, and can be used with other beams and joists where extra load bearing capacity is required.

20160729Universal beams offer added strength as a result of their shape. Image by Bbanerje, used under the CC BY-SA 3.0 license.

(This article comes from BUILD editor released)

Universal columns

Constructed of polypropylene homopolymer, these columns have a multitude of applications in life sciences as well as in clinical applications. Polypropylene is chemically resistant to weak acid and alkali.

This universal column has a reservoir section, a straight resin section and a luer lock compatible tip. The reservoir has a wide-mouth opening for easy pouring. The total capacity of the reservoir is 25 ml.The reservoir is segmented at various levels for easy visual level references. The straight resin section has a capacity of approximately 5 ml.

(This article comes from Evergreen Scientific editor released)

Bearing Piles

There are a multitude of different types of bearing pile, varying in depth, diameter and reinforcement. The bearing pile takes its load from its shaft and toe and therefore the load it can take greatly depends on the soil stratas encountered.

For instance a bearing pile in clay provides more shaft friction than end bearing, whereas a pile in sand takes more load from its toe than the shaft. This is due to the physical makeup of clay and sand and how they react to loads.

We are able to install bearing piles on a wide variety of sites. These have previously included:

  • Housing Apartments / Tower Blocks
  • Commercial Buildings
  • Bridges and Main Roads
  • Leisure Buildings
  • Science and Medical Buildings

The bearing piles we install typically vary in diameter from 300mm to 900mm, but we can adapt our piling rigs to other diameters.

The piles can be installed to to depths of anything up to 28m and we can install varying amounts of reinforcement depending on the specified loadings.

(This article comes from Rock & Alluvium editor released)

Soil Stabilization

Soil nailing is an economical technique for stabilizing slopes and for constructing retaining walls from the top down. This ground reinforcement process uses steel tendons which are drilled and grouted into the soil to create a composite mass similar to a gravity wall. A shotcrete facing is typically applied, though many architectural options such as precast panels or “green” vegetated cells are available for permanent wall facings.

Soil Nailing Advantages

  • Used to follow irregular curves.
  • Equipment is portable for tight spaces.
  • The technique is flexible, easily modified.
  • Creates less noise and traffic obstructions.
  • Less impact on nearby properties.
  • Requires minimum shoring space.

(This article comes from Rembco Geotechnical Contractors editor released)

What is the benefit of using a micropile?

Micropiles are installed for new foundation support or for underpinning existing foundations. They are also installed diagonally for tension, tiebacks or soil nails. They are a perfect solution for drilling extremely hard rock and soil layers. We can also install micropiles in spaces with low overhead clearance, basements and limited access areas to stabilize structures or for additional foundation support.

Micropiles are a great solution when using conventional concrete caissons is not possible. Problem conditions can be limited access job sites, soils with high blow counts, drilling into bedrock, obstructions, nearby structures and unstable areas such as sinkholes, underground rivers and caves.

Common Uses of Micropiles

  • To replace deteriorating foundation systems
  • To provide extra support for structures during renovation
  • Underpinning an existing structure for stabilization or for re-leveling
  • To provide pile foundations where access, geology or environment prevent the use of other methods
  • To support structures affected by adjacent excavation, tunneling or dewatering activities
  • To provide a fast, effective alternative to more traditional underpinning methods

(This article comes from Park Range editor released)

DEEP FOUNDATIONS

PILE FOUNDATIONS

A pile is basically a long cylinder of a strong material such as concrete that is pushed into the ground so that structures can be supported on top of it.

Pile foundations are used in the following situations:

  1. When there is a layer of weak soil at the surface. This layer cannot support the weight of the building, so the loads of the building have to bypass this layer and be transferred to the layer of stronger soil or rock that is below the weak layer.
  2. When a building has very heavy, concentrated loads, such as in a high rise structure.

Pile foundations are capable of taking higher loads than spread footings.

There are two types of pile foundations, each of which works in its own way.

End Bearing Piles

In end bearing piles, the bottom end of the pile rests on a layer of especially strong soil or rock. The load of the building is transferred through the pile onto the strong layer. In a sense, this pile acts like a column. The key principle is that the bottom end rests on the surface which is the intersection of a weak and strong layer. The load therefore bypasses the weak layer and is safely transferred to the strong layer.

Friction Piles

Friction piles work on a different principle. The pile transfers the load of the building to the soil across the full height of the pile, by friction. In other words, the entire surface of the pile, which is cylindrical in shape, works to transfer the forces to the soil.

To visualise how this works, imagine you are pushing a solid metal rod of say 4mm diameter into a tub of frozen ice cream. Once you have pushed it in, it is strong enough to support some load. The greater the embedment depth in the ice cream, the more load it can support. This is very similar to how a friction pile works. In a friction pile, the amount of load a pile can support is directly proportionate to its length.

In practice, however, each pile resists load by a combination of end bearing and friction.

(This article comes from UnderstandConstruction.com editor released)

Hollow bar anchors with proper drill bits is efficient

Hollow bar anchors are a threaded drill rod with sacrificial bits that are advanced to the desired depth. The hollow bar anchors are grouted through the center of the drill string and out the end of the sacrificial bit.

This process creates a cement column that is reinforced in the center with the steel drill string. Hollow bar anchors can be used as tie backs, tie downs, rock anchors, soil nails  and micro piles. Their versatility and compact equipment meet the needs of many challenging applications.

There are three types of drill bits used on hollow bars. The highly versatile carbide cross cut bits, carbide button bits for hard rock and stepped clay bits for cohesive clay. The type of drill bit and size is based on the soil type and the desired capacities. Larger boreholes provide higher load carrying capacities and more grout cover. The grout cover protects the anchor bar from corrosion but galvanization is also available. Depending on the soil type, a 3” diameter bit with grout pressure can create a 6” to 8” diameter grout column. Production rates are higher when using hollow bar systems as compared to traditional drilled anchors. This is especially true when drilling at sites with low headroom or where there is the risk of bore hole collapse.

(This article comes from Tildee.com editor released)

Self-drilling bars for tight spot micropiling

Self-drilling bars within the extensive range of the Minova MAI range of foundation and stability control products are moving beyond their traditional applications in underground construction and are being used also as micropiles. Vital to the protection of infrastructure above underground excavations, the expanded use of the SDA self-drilling bars provide efficient underpinning of the foundations of buildings and for stabilizing ground around excavations particularly in hard-to-reach sites with limited working space.

SDA micropiles can be installed in every ground type and can withstand, reliably, both tension and compression loads of up to 2,750kN in tension and up to 1,910kN in compression. The hollow-bar design of the self-drilling system offers a single action for drilling and grouting. As an efficient method of stabilizing the subsoil, micropiling is becoming an ever more important method for preventing settlement of foundations for the long term.

Conventional micropiling has several major limitations. These include the time-consuming multi-step installation process, the fixed length of reinforcement or their complicated extension, and their design for just compression forces and not for tension, being limited by the load capacity of their connections and pile-caps.

Minova MAI SDA hollow-bars overcome these limitations and make the installation faster and more efficient with their one-step process. The bar is drilled into the ground and cement grout is injected through the hollow rod in one operation. During drilling, the grout stabilizes the borehole to prevent it collapsing. Once installed to the required length and after full hardening, the grout transfers the load from the bar into the surrounding soil. The simultaneous grouting ensures full and uniform coverage of grout along the full length of micropile. Extension couplings provides lengthening of the micropiles and the bearing capacity of the connection remains the same as of the bars.

Comparatively small-scale drilling equipment can be used to install the SDA bars as micropiles in tight spaces or with limited headroom. With little vibration or noise, the drilling process itself causes minimal stress on the surrounding structures.

In diverse ground conditions, from gravel, sand, or clay, or on sites with insufficient structural integrity, the Minova SDA self-drilling bars as micropiles are versatile in their application, quick and reliable in their installation, and compatible with conventional drilling equipment. Once installed, they are an effective means of preventing settlement and helping to increase soil stability.

(This article comes from TunnelTalk.com editor released)

Guide to the best rope to use for anchor systems on your boat

Hi Guys, there are a plethora of rope varieties that can be used on drum winches. Actually that’s one of the great things about drum winches! However not all ropes are created equal.

Now the first thing you should know is there are two basic categories in which most ropes can be classified, double braid and 3 strand. In the smaller diameters (6, 8, & 10mm) double braid is the preferred choice due to its high breaking strain and small diameter. Double braid is available with two different fibers, polyester or nylon.

Double braid polyester is a common choice due to its cheaper price, high breaking strain, UV rating, and abrasion resistance. However polyester lacks any stretch in the fibers, so if you are stretching polyester the fibers are actually being damaged. When using polyester anchor line a sacrificial nylon ‘top shot’ should be employed.

Double Braid Nylon is a great all around choice for its ability to stretch time and time again without damaging the fibers. The strength is similar to that of polyester with slightly lower abrasion resistance. Nylon has a high UV rating and is also around 30% more in price than polyester. Double Braid Nylon is the only anchor line LSM supply.

Next is three strand. Three strand anchor lines can be made from PP, Polyester, Poly Blend, Nylon, or natural fibers. The most common three strand today is PP, and although good PP is very nice hand anchor line there is little if any left around today. Most PP is of the ‘cheap and nasty’ variety. Due to its relatively low breaking strain per diameter it is not an ideal anchor line in sizes less than 12mm and therefore not an ideal drum anchor winch line.

Three strand polyester or poly blend is a good cheap drum anchor winch line in the larger sizes. The price is a fraction of the cost of double braid yet in sizes over 10mm it has a relatively high breaking strain. 3 strand will also stretch a little given the ‘coiled nature’ of its assembly. So when 3 strand poly blend ‘stretches’ its not actually the fibers that are stretching, rather the coil tightening on itself. For the first part anyway. We do not recommend three strand under 10mm in size as the breaking strain is exponentially reduced and much lower than double braid counterparts.

Three strand Nylon is perhaps the ultimate in larger diameter anchor lines. Its tough, has a high amount of stretch, high UV rating and can be used for decades. Again however the advantages of three strand nylon start around the 12mm diameter mark. Three stand nylon is the anchor line of choice, just below double braid nylon, in larger vessels. Price for three strand nylon is similar to double braid polyester. Three strand nylon is also the preferred choice for many Windlass anchoring systems.

Dymeema. Now a lot of people confuse double braid with dyneema. Dyneema is the same sort of fiber braided fishing line is made from. Like double braid polyester dyneema has no stretch, so if using dyneema a shock absorbing ‘top shot’ must be used. Quality dyneema is very expensive, however it can be very beneficial for extending the drum capacity on your winch.

So how do you know what you are buying in anchor line? Well unfortunately it can be very difficult to tell the difference between anchor lines (see picture below), and this is where reputable dealers come in. You cannot fake a good reputation guys. Both Poly and Nylon can have any number or color of ‘flecks’, or it can be pure white, so colour or lack thereof is no indicator of fibre material. In both doubl ebraid and 3 strand Nylon is typically a little less shiny than polyester.

Note the image. The first two ropes on top are double braid nylon. The next two are double braid polyester. The three strand variety pictured is a quality PP, and finally the blue line at the bottom is 5mm AU made dyneema.

(This article comes from Lone Star Marine editor released)

Helical Piles and Helical Piers are The Same Product

Helical piles and helical piers are two terms that refer to the same product. These terms are commonly used and both refer to the exact same product.

Uses

Helical Piles are used to secure residential and commercial buildings, retaining walls and other deep foundation applications, and on new construction as well as repair and renovation work. Helical Piles are an affordable solution for foundation repair where soil conditions require deep piles to be installed. There are several advantages for using helical piers.

Advantages of Helical Piles

  1. They can be used on new construction projects, and will soon become mandatory in flood prone areas. They are perfect for new construction and any projects built on unstable soil. , contractors install helical piers under the existing foundation Rather than removing the existing foundation this not only save time but will save the homeowner money. This is both cost effective and environmentally friendly.
  2. Helical piles can be installed in small areas we have portable equipment that can be used in very small spaces. Compared to other pile and pier methods another advantage to helical piles is that in most cases no concrete is used, therefore the next phase of construction can begin immediately
  3. Helical piers have changed the way foundations are designed and built. Helical steel piers can be installed in place of conventional driven wood, steel, auger cast, and caissons. These piers are faster and install with a minimal amount of landscaping damage. A hydraulic auger mounted on a skid steer or mini-excavator is used to screw in the helical pile thru the soil as torque is monitored to achieve required load capacities.
  4. This environmentally friendly system provides a clean and quick installation procedure to keep projects on schedule. A steel plate is fastened on top of the pile and encased into the new concrete foundation. The pile can be loaded immediately.
  5. Unlimited uses for helical piles: Home extensions, underpinning existing foundation, concrete footings, foundations, and retaining walls. As well as Concrete slabs, decks piers, generator pads, commercial projects, and reinforce existing foundation for second story additions.

(This article comes from Helical Piles NY editor released)