ABOUT

French drain, also known as ‘drain tiles’ or ‘land tiles’, are trenches filled with gravel, sand or rocks. Their main function lies in diverting water away from a particular location. They protect buildings and homes from permanent damage caused by water infiltrating through building foundations.

The main purpose of  French drain is water distribution, for instance, water running out of standard sewage treatment systems. Additionally, internal French drains are commonly used behind retaining walls (building structure that keeps rock and dirt away) to ease the pressure caused by large volumes of water.

HISTORY

The French drains, in its initial stages, were simple and basic trenches placed from high to low elevation and filled with gravel and rocks. It was Henry French from Massachusetts who created the tiles that modern French drains consist of.

Newer varieties of French drains have perforations while other variants include filter drains, collector drains, fin drains and dispersal drains.

TYPES OF INTERNAL FRENCH DRAINS (BASED ON INSTALLATION)

French drains are installed around building foundations in two ways. The first is by burying tiles against the foundation walls on the exterior. The second is by installing drain tiles on the interior side of the basement below the basement floor.

HOW TO INSTALL A FRENCH DRAIN

1. Digging a Trench: French drain is constructed by digging a trench of varying width and depth. A depth of 8 to 12 inches and a width 5 to 6 inches are the most common size that satisfies most drainage requirements.

2. Ensuring a nice slope: Grading and survey issues are the critical elements for water to actually flow in the right direction. Check extremely short drainage stretches to ensure there exists a slope of at least 0.5 percent and a grade of 1 or 2 percent.

3. Fill it With Gravel: Now add gravel to the trench leaving some inches off its surface. The gravel need to measure roughly between 0.5 and 1 inch.

4. Covering with coarse sand: Now fill the top layer with 3 to 4 inches of coarse sand. This permits the growth of turf so that the underlying trench is camouflaged. Remember – the sand must be coarse. Otherwise, proper water drainage won’t occur.

5. Turfing the trench: You can either turf through seeding or simply permit them to grow from adjacent sands, especially if it is of a spreading variety. You may even lay grass over sand. For this, ensure the soil is removed from grass roots, so that the sand doesn’t get contaminated with finer soils

6. For internal drain systems the sloped pipe will run to a drain or dewatering pump which will transport the water to a desired location. Moreover, the top of the drain would be covered by a vapor barrier and then concrete to be flush with the existing floor. (We will discuss interior french drains in greater detail in the future)

FRENCH DRAIN ANATOMY

Originally, the French drain was just a trench filled with round-shaped river rock. The principle idea behind it was that the trench would provide the nearby surface water a place to sit while it slowly dissipated to the soil below. Considering the amount of rainfall received each year in the United States, just giving the water a place to sit isn’t enough. Rather, give a viable outlet to the water. This is the main reason why most drainage firms use drainage pipes for internal French drains.

An French drain is typically covered with geotextile socks that keep it free from debris and silt. Additionally, its drain pipe can be connected to green space, sump well or other such outlets.If the French drain is placed beneath the lawn, the drain can get encapsulated in the landscape fabric replacing grass and soil on the top. If placed outside the lawn, a river bed of 6 to 8 inch width on the top may get created which is both functional and decorative. In this system, the surface water goes straight through river dock to the pipe below getting carried to the water outlet.

“Keystone Basement Systems, Inc. is a foundation repair company. KBS is not, however, a engineering firm and should not be considered as such.”

Steel is the most common and simplest form of metal alloy in the world with varying amounts of carbon. Iron is the major component of steel with less than 2.15% of carbon. The metal with greater content of carbon is called as Cast-Iron. Iron contains impurities like Manganese, Sulphur,Phosphorus,Tungsten,Vanadium and Silicon that are removed and other desirable alloying elements are added by a process called Slag.Steel has been in use since 1400 BCE and is popular in the construction industry for its strength and malleability characteristics.

Production Of Steel:

Steel was manufactured first through cementation process, in which iron bars are heated in a closed furnace with charcoal such that the iron surface receives high carbon content. Three modes of steel production are currently used which include:-

 Basic Oxygen Process
 Bessemer Process and
 Open Hearth Process

Siemens-Martin process is popular as Open Hearth and produces large quantities of basic steel. In this process the charge is laid in a furnance called “Open Hearth” where the wrought iron is melted with steel scrap by pre-heating air at at a very high temperature to produce steel in large quantities. With the discovery of Basic Oxygen steelmaking process, Open Hearth process has become history.

Yet another modern development is the ‘Electric Arc Furnace’ which manufactures high grade steel in large proportions using positive temperature control, desulphurization, de-oxidation and freedom from fuel contaminated products. The benefit of this process is it allows the steel mill to vary production according to demand. Thus allowing a large reduction in energy consumption used in producing per unit weight of steel.

Types Of Steel And Their Uses:

A wider variety of alloys are available in the market with improved steel making techniques. Steel is classified based on its carbon content. Approximately there are 3,000 catalogued grades in the market.

Steel high in carbon is used for cutting tools and dyeing purposes while medium or low-carbon steel is used for structural and sheeting purposes. The qualities of steel are enhanced by adding other metals or elements. Aluminum imparts tensile strength and smoothness to steel. Nickel is most widely used of the alloys. It not only is nonmagnetic, but also possesses high tensile properties like high carbon steel, but without any brittleness. Chromium Nickel steel has shock resistant properties, which make it highly suitable for armor plates. The high tensile strength of chrome steel makes it suitable for use in airplane and automobile parts.

Factors Contributing To The Strength Of Steel:

Compared to concrete, steel has high tensile and compressive strength, which means that steel responds to crushing and stretching force in a similar way. Below are some common elements added to steel to enhance its strength:-

 Carbon: It enhances the tensile strength of steel by 0.85 %, but reduces its weldability and ductility.

 Manganese: Manganese benefits the surface quality of steel, especially resulfurized steel. It enhances the strength and hardness of steel, but decreases its weldability and ductility albeit to a lesser extent than carbon.

 Phosphorus: It increases the hardness and strength of steel, but reduces its notch impact toughness and ductility. The adverse effects are magnified in tempered and quenched high-carbon steels and hence phosphorous is always added in small amounts.

 Sulphur: Sulphur decreases the notch impact toughness, ductility and weldability of steel, more so, in a transverse direction due to which sulphur levels are kept at minimum. The only exception to this is free-machining steels, where sulphur improves the machinability.

 Chromium: Chromium increases the oxidation resistance, corrosion resistance and high temperature strength (hardenability) of steel. Chromium, when used with Nickel, produces steel with superior mechanical properties. The strength due to chromium increases with the rise in temperature.

 Nickel: Being a ferrite strengthener, Nickel does not form steel carbides. It stays in solution within the ferrite, toughening and strengthening ferrite phase. It increases the impact strength and hardenability of steel.

 Aluminum: Aluminum acts as a deoxidizer, controlling the grain size in reheated steels.

 Titanium: It retards the grain growth in steel, enhancing its toughness. It also makes sulphide presence in molten steel to be more globular compared to elongated, improving the ductility and toughness in transverse bending.

Steel For Construction Materials:

The versatility and reliability of steel makes it useful in construction. Mass production of steel was virtually impossible until mid 19th century, rendering it impossible to construct steel buildings. Steel has presently become one of the most reasonably priced building materials. You can use it to create an entire building, or combine it with other materials for construction.

With “Green Construction” gaining popularity, growing interest to use “Steel” is becoming more evident. Steel is one of those building materials that allow recyclability option without degrading its structural strength and other chemical properties to the specifiers of the construction industry.Everything, right from covering walls and roof is made from steel. Forming a complete building with steel would make it feasible to erect affordable construction without giving up on factors such as design, safety and durability.

Steel buildings were previously inhospitable and unattractive. Now, you can receive stylish buildings made from steel that create a comfortable atmosphere and also the great look.  Steel is also combined with other building materials like concrete.  Usually, in skyscrapers, steel is used to create a tough frame system, while concrete is used for roofing, floors and walls.

“Keystone Basement Systems, Inc. is a foundation repair company. KBS is not, however, a engineering firm and should not be considered as such.”