WALL STRUCTURES

Post 682 –by Gautam Shah

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Wall structures have been prime structure for community purposes like, flood protection, irrigation, defense, terrain contouring and against erosion of land. These, perhaps preceded the walls erected for construction of dwellings. The builders from ancient times, were innately aware of the difference between a wall carrying side thrusts and bearing vertical loads. And accordingly the forms and techniques of constructions were different. The walls carrying side thrusts followed the natural angle of repose (the steepest angles at which a sloping surface is formed of loose material remains stable). The walls carrying vertical loads were designed with concern for lateral stability, and to a lesser extent worry about load bearing capacity.

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The idea of a column, as a ‘zero-sized’ wall, (like the Stonehenge) and of pillars (obelisks) may have come from tree trunks. Wood scaffolds were used for painting tall cave walls and ceilings. A series of props or poles, were used as piles or spikes for quicker formation of linear structures, such as in under-water constructions, floods, wet soils, or support against sand like loose soils.

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15 Walls

2 Double lined Groyne Schobuellbuhne042006

Earthen Wall structures for embankments or dams, for water flow regulation, storage, prevention of land erosion, against flooding, access-way (road) construction, for irrigation or navigation channels were constructed by combination of deposition or cutting-dressing. But the skill rested in exploiting the existing contours of the lands. Such structures were large and affected the entire community. For participation of large number of people, clear perception of the project and its benefit was necessary. It is apparent that such projects were executed during certain season. These were continuing efforts as added upon and improvised by several generations. Such lasting efforts can occur in societies that are politically and socially stable.

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Other walls were erected in the form of city-town walls to protect the community, and monumental structures related to burial facilities. These walls due to their extent gave impression of monumentality, and were gravity-stable and invincible forms against the invaders or marauders. Walls defining passageways are for land mass retention and ceremonial demarcation of walkways. Town walls and monumental walls, both were not ‘load-bearing’ structures. Both also related to access by large number of people, often in processions. The inevitable entry point was well marked in scale and position-location.

16 Passage tomb of La Hougue Bie by © Copyright Bob Embleton and licensed for reuse under this Creative Commons Licence.

Protective walls were often constructed as tall fences. These were made insurmountable by various means like an enhancement of height-width factors. Width was increased by forming a ditch on the face of the wall, and height was added by constructing the wall over a natural steep edge of terrain. City walls in some areas were constructed of tree trunks or wood lattices.

5 Pallisade like fence as a wall against calalry United States History Civil War, 1861-1865

Palisade in Celtic village Wikipedia image by Zureks

A palisade, was a defensive fence (also called a stake-wall or paling) formed around the military camps by Greeks and Romans. It is formed of wood stakes or tree trunks placed in a line. A groyne is a similar, but low height wall structure, a hydraulic entity for interrupting the free flow of water and restricts the movement of soil-sediments from coastal area.

7 Groyne at Mundesley Norfolk Wikipedia Image by MichaelMaggs

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A levee, dike, dyke, ditch, embankment, flood-bank or stop-bank, are naturally occurring long ridges or artificially constructed walls to regulate water. These are usually of stone and earth, and follow the course of a river. Levees and other structure require constant care by organized society. Some of the earliest levees were constructed by the Indus Valley Civilization (2600 BC), Egyptians to manage the floods of river Nile, in Mesopotamia and China. The word Levee or F. Lever, literally means ‘to raise’.

Stone lined trench bach_meadow_away_railing_walk-746630.jpg!d

The Greek geographer Pytheas noted in 325 BC, that ‘more people died in the struggle against water than in the struggle against men’.

The word Dyke (dijk) indicates, both trench and bank for water management. The word Ditch derives from dic, dick or dig, meaning to digging a trench and raise the banks with the excavated soil. Such earthworks acted as horizontal walling to deepen water channels, enhance the flow-rate and water carrying capacity. The water channel shaping by the side walling structures provided reliable lanes for waterways. These wall structures were formed to reduce the erosion by water flows, waves and winds.

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The first dikes and water control structures were built and maintained by those directly benefiting from them, mostly farmers. As the structures got more extensive and complex councils were formed from people with a common interest in the control of water levels on their land and so the first water boards began to emerge. These often controlled only a small area, a single polder or dike. Later they merged or an overall organization was formed when different water boards had conflicting interests. The original water boards differed much from each other in the organization, power, and area that they managed. The differences were often regional and were dictated by differing circumstances, whether they had to defend a sea dike against a storm surge or keep the water level in a polder within bounds. In the middle of the 20th century there were about 2,700 water control boards. After many mergers, there are currently 27 water boards left. Water boards hold separate elections, levy taxes, and function independently from other government bodies. -Flood control in the Netherlands Wikipedia

Mycenaean city walls

City walls are elaborate ‘fencing structures built from stronger materials to fortify a territory. The fort walls were symbols of power, so the scale was grandiose. These walls were planned at most select location, adding upon whatever natural defence features were available. Appropriateness of the site also rested on logistics of supply, of which food-fodder and drinking water, even during seizure condition, was very important. Forts housed a populated community and to sustain it, also included structures for defense preparedness and for offense capacity like ditches, gates, embankments, watchtowers, crenelation, etc.

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A moat is a ditch or long pit around a settlement with or without a fence or fortification. Moats were created by reforming the existing terrain features, or dug as a new one. Fortified structures, like castles were once sited over difficult terrains, where some natural features such as hills, elevated lands or rocky landscapes were available for some protection. Moats were additional defence provisions, formed at vulnerable spots. The difficult terrains, however, make it difficult to reform existing terrain, or excavate a new trench. Digging a moat was not only labourious, but the management of the excavated material equally difficult. The excavated stuff was used to back support the fort walls, or raise the level of internal grounds. Moats were formed along with construction of fort walls.

Linear Defense wall GorganWall

Some of the earliest defensive walls were linear formations and not any surrounding or enveloping forts. These were long barrier walls with open ends or terminating into hillock or large water body. These linear walls marked a territorial edge or boundary of the kingdom. Such edge walls had to be very extensive to be effective.

Sumerian King Shulgi of Ur, 2038 BC., built a wall that was 250 Kms long, between the Tigris and Euphrates rivers, to keep the invading Amorites out of Sumerian lands. Great Wall of Gorgan (restored and renovated by the Sasanian Persians in the 5th or 6th C) was 195 Kms long, and included more than thirty forts along its length. Great Wall of China was built as several small independent units, possibly first at vulnerable points, which were ultimately joined together during the Ming Era. It was as a freestanding regional scale defensive structure. Similarly the Anastasian wall (the Long Walls of Thrace) of the Byzantine Empire (469 C) located in modern Turkey was also not anchored at either end to any terminus. All such walls proved to be ineffectual as enemy army marched around the ends. The most known wall structure, Hadrian’s wall of Britain was built by Roman Emperor Hadrian (122 AD) to prevent frequent incursions.

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WALLS through HISTORY

Post 503  by Gautam Shah

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Walls are erected as structures to bear the roof, to barricade settlements, to define passageways and to protect lands from tides and floods. Walls of abodes being too small in scale and strategically less important for continued care, rarely survive. Barricades for settlements such as fortifications are of grand scale and designed to resist ravages of time. Walls defining passageways are for land mass retention and ceremonial demarcation of walkways. Walls created for protection of land from sea water ingress and flooding, have remained all time necessities so rebuilt and reformed.

Natural wall > Organ Pipes, Victoria, Australia. Pic by : Nick carson at en.wikipedia

reconstructed Goseck Circle (prehistoric solar observatory) image by Kreuzschnabel/Wikimedia Commons, License: artlibre

US immigrants forming a wall of covered cart around the night halt camp

Walls are super structures rising above the lands, and are also subterranean features for platforms, dykes, canals and bunds. Walls are formed by nature due to directional erosion. Man-made walls are created by staging of the land, vegetation or snow mass. Fortification walls are of many types situational conditions of nature, man-made structures of animals, carts and building materials. All man-made structures have peculiar geometry that makes it easy to recognize in their trace forms or buried under lands or waters.

Sketch of a cross section of the Newgrange passage grave made by William Frederick Wakeman (d. 1900).

Facade of the tomb as reconstructed by archaeologists, detail > Wikipedia image by Author Aligatorek

Walls are parallel to gravity forms. The horizontal dimension or the length is its distinguishing feature. Walls of stacked materials like clay, mud, stones, snows, vegetation etc., are wider than their height, but structured or arranged walls are several times thinner than their width. Walls thinner than their width are susceptible to horizontal displacing loads including wind, water and earthquakes. Such walls are buttressed intermittently with abutments, flanges or angular layout.

Ancient wooden wallimage from torange_biz free photobank

Hadrian’s wall just east of Greenhead Lough, Northumberland

Roman walls of Lugo

Historically Greeks created pristine walls with coursed masonry. Romans created brick and concrete walls with built in lining that were often had variegated stone facings sourced from old debris. Roman walls in interior spaces were plastered with marble powder and polished to a very glossy finish. Walls were decorated and painted by stucco system. Marble and glass mosaic in figures and patterns were applied on walls. Byzantine walls were finished the same way, but unlike the flashy colour scheme of Roman villas and Thermae, were simpler. Byzantine buildings used marble and mosaic bands running across the interior walls.

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Mykene Treasure of Atreus Tholos Pic by Wikipedia author Adam Carr

Egyptians painted the interiors with their limited tonal vocabulary, but using gilding extensively. Babylonians used ornamental poly-chrome brickwork, often with low relief work. In early Gothic period the walls were being flooded with light so the structural contouring or definitions were very important, rather than the wall treatments. Wall ornamentation was like the tracery pattern employed in windows. Panellings were used at lower levels of otherwise tall rooms. Gothic period also saw introduction of external non load-bearing or partition walls. In buildings other than church walls did not require such vast openings. Areas between openings in interior and exterior began to form into alcoves or niches to filled in with statuettes.

River gallery of the Château de Chenonceau, designed by Philibert Delorme and Jean Bullant Wikipedia Pic > Creative Commons Attribution-Share Alike 3.0 Unported license by Author Wladyslaw (talk)

During Renaissance these intermediate wall areas were highly rusticated. Windows were visually enlarged by decorative appendages. A modulated vocabulary of alternating wall and window treatment was established. These vocabularies, however, did not evolve across the floor except by repetition. Post Renaissance period saw entire facade walls being designed as one unit overcoming the horizontality of floor divisions and straight roof lines. Facade walls now became undulating not in the plan but also in elevation. Japanese shoji partitions serving the purpose of door, window and a wall divider. It inspired many architects in early 20th C to design interiors with relocatable partitions systems. Space and bubble structures dissolved the wall as a definition.

Hexagonal external cladding panels of roof in Eden Project Biomes (Cornwall, England,) Wikipedia Pic by Author Etan J. Cal

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OTHER WALLS

Post 266 – by Gautam Shah

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Walls have been part of architecture to bear the load of super structures, resist the thrusts and divide the spaces. Barrier walls have erected against, invasions, natural forces such as winds, storms, sea water ingress, floods and tsunamis, noise, and other energies. Political walls isolated or confined people on moral, religious or criminal grounds. Natural terrain formations are walls such as the hills, cliffs, mountain ranges, causeways.

Wave rock

iceland_beach_water_rock_stones_steep_wall-987761.jpg!dThe essential engineering formation of walls have been the same as in architectural structures. The walls are constructed as composition of elemental units placed in substantially in consideration of the gravity, and to smaller extent against the direction of thrust and friction resistance offered by the mass movement of the ingredients. Walls are created by engineered design where materials either achieve homogeneity through composite formation or make a geometric arrangement towards a unified system.

Tustrup_jaettestue1280px-115_-_Cuzco_-_Juillet_2009A levee, dike or dyke, embankment, flood-bank or stop-bank, are walls by exploitation of natural features or formed to prevent flooding of the adjoining countryside, waterways to provide reliable shipping lanes, confine the flow of the river or high tide ingress. Breakwaters are coastal defence structures for weather protection and long-shore drift.

Sacramento_River_LeveeOosterscheldekering,_the_largest_of_thirteen_Delta_Works'_dams_and_barriers._1Vyrnwy_dam

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Barriers against Noise have been of two types: one that deflects the sound and the other that substantially absorb or dampen the noise. These have been placed on road and rail sides, airport runways and on Metro railway stations. The railway platform barriers also act as safety walls.

Panoramio_-_henkiedenkie_-_Noise_barrier_DelftParis_Metro_St_LazarePolitical walls are ‘designed to keep people in or out, while some simply keep people apart’. The walls have divided nations and assets, isolated the populace from foreign influences, controlled immigration, countered the invasions. Non-wall barriers have been erected to contain spread of diseases like Plague, Aids, TB, Polio or Ebola. Walls have erected to very tall and wide, impossible to negotiate. Walls have been barbed or electrified, made of impossible to shear cut materials, multi-layered with infra-red cameras and motion detectors. Yet in theory, no wall should be impossible to scale. ‘Show me a 50-foot wall and I’ll show you a 51-foot ladder, US Secretary of Homeland Security Janet Napolitano said about the massive and highly secured border between the USA and Mexico’.

Israel-Palestinian_Wall_Ich_Bin_Eine_BerlinerModern political walls have manifested in Berlin, Germany, Middle East, US-Mexico, Northern Ireland and N-S Korea. Political walls have a duality of differing views on either side. It attempts to sustain a status-quo at any cost. It takes only time to force the change in the mind set. Europe was and still is made of divided nations, but EC has caused few common things such as currency, taxation and exchanges.

prayer-650426_640Walls have been cultured’ by their long-lasting ethnicity. Some have been associated with religious myths, legends, events, people or time.

Hadrians_Wall_05Fort walls were supposed to be defence structures but have been for display of power due to their form, size, location and function. Fort walls signify a point of change in political environment, which could be at one extreme, very real, and at the other extreme only indicative or metaphysical. Fort walls have been endowed with importance by additional structures such as gates, towers, abutments, ramparts, bulwark, bastions, Bastille, battlements, belvedere (chhatri), buttresses and campaniles (bell tower).

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Champaner_citadel_walls

The word wall comes from Latin vallum = an earthen wall or rampart set with palisades, a row or line of stakes, or fortification. The Latin word murus meant a defensive structure of stones, in later English, it is used for an external wall and internal sides of a room. In German, the words Wand and Mauer, and in Spanish the pared and muro have distinctive meanings.

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WALLS and Buildings

Post 244 – by Gautam Shah

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A wall is a planner structure, generally vertical, with a proportionately narrow thickness in comparison to its height and length. It is a barrier system, like fences, barricades, partitions, etc, and used for dividing or enclosing a space. Its most distinguishing function has to bear the load. It bears its own weight -the self load, and also other imposed loads of the super structures or sideways thrusts. Walls ultimately transfer all the loads, own and imposed loads or thrusts to the earth. One of the most efficient load transfer systems to the earth is in perpendicular direction to the gravity. As a result, in all structure compositions, the vertical walls predominate.

Walls of Stairs Kolkata India

Allen Lambert Galleria Toronto an atriumspace by Santiago Calatrava that connects several heritage buildings along the side of it Wikipedia Image by Secondarywaltz

Imposed loads on walls emanate from other structural systems of the buildings, such as floors and roofs, beams, services, etc. and from the occupancy of these systems, like ‘live’ loads of people, flora, fauna, goods, storage utilities. Thrusts from within the structures are transferred by the walls to other bearing elements, or resisted and converted into a gravity bearing vertical component. These loads include from arches, beams, vaults, etc. Thrusts also bear upon the wall due to the lateral resistance provided to other elements such as water, grains, sand, soil, etc. and retained liquids or gases. Walls also endure pressures arising due to dynamic movements of live loads and shifting dead loads, earthquakes, and energy vibrations of sound, wind, etc.

metal-glass facadesWalls carry distributed loads, but frequently loads concentrated at a point induce local stresses and failures. Walls also fail, under excessive distributed loads, at its weakest section, get crushed or deformed depending on its homogeneity. When a wall has width equal to or less than its length, it becomes a column, and loses its meaning. Moreover, a wall that has a height equal or less than its width, remains an in-fill course or a layer only. Walls without any external down bearing imposed loads are called partition walls.

Uppsala cathedral wall

A wall carrying only side-thrust is called a retaining wall. A wall which carries the load of upper structure and also retains earth is an abutment wall. A gravity wall resists the side thrust of retained material by its dead weight. Gravity walls primarily have a trapezoidal section, with wider part forming the base. Cantilever retaining walls have ‘L’ or inverted ‘T’ section. A buttressed wall has additional intermittent pieces of lateral walls on the open face, to strengthen the mass. A counter-fort wall has a similar system (often as a structure in tension) on the inside or the loading face.

Wall Hazara Rama temple Hampi, Karnataka India Wikipedia Image by Ms Sarah Welch

Tabo Gompa - old walls and chortens Wikipedia Image by John Hill

Retaining Walls

Walls as barriers resist variety of forces or energies. A translucent to opaque wall can reduce light transmission. A wall of an absorbent material and geometric configuration is used in attuning sounds. Latticed walls as barriers filter out select elements. Small height walls are used as compound or estate walls and as parapets. Dispersed vertical linear elements used as non-continuous barricade function like walls. Curtain walls are rigid membranes that envelopes a building to protect it from winds and rains and many instances bear the surface shears.

Wall of Porta San Giovanni Wikipedia image by

Edward Durell Stone US Embassy Delhi Latticed wall

Walls are ‘loaded’ along and across the width section, and sometimes along the length-section. To bear a load, a wall is expected to have adequate surface cross sectional area in a plane parallel to the gravity. These surface component are made of width and length of the wall. Theoretically, a wall can have an infinite length and single size module of width. Nominal walls however, are required to bear a variety of loads, thrusts and stresses. So walls need some sectional depth, depending on the integrity or homogeneity and strength of its materials, in addition to the geometric formation and composition. Height of a wall is a finite element, though theoretically a wall could be infinitely tall. A tall wall, proportionally, turns into a slender structural entity. Wind and other vibrations over the surface of a tall or slender wall are random (stochastic) motions. These cause dynamic effects in many different directions. So even if depth (thickness) of the wall due to high integrity of material, composition or geometry, can bear the loads, the transmission of loads to the ground is not harmonic or consistent.

Walls of Red Fort Delhi India

Walls of Hyderabad (Pakistan) Fort -Pacco Qillo Wikipedia Image by MUrad Ali Shah Bukerai

Very thin walls are used in shells, domes, tanks, plates and membrane structures such as balloons. These are often called shell or membrane structures depending on their structural transmission. These structures often have indistinguishable wall and roof elements. A shell structure is classed as compressive structure, whereas a membrane structure like a balloon is classified as tensile structure. Thin structures are used for their light weight and economy. Membranes are thin and pliable materials or formed by ‘bloating’ or stretching a material along its plane. Membranes ‘wall’ or surfaces can carry well-distributed loads, but are incapable of taking any pointed loads, unless material is tear or puncture resistant. Boat sails and circus tents are examples of membrane structures. When a hard, homogeneous and rigid material is used for creating a thin wall structure it is called a plate or shell structure.

Walls of wonky brick building crooked old masonry house

Walls of Cooling tower at Thermal poer station Neyveli, Tamil Nadua India Wikipedia Image by NLC India Ltd.

Sail Ship -a membrane wall

 Walls of space vehicles and stations in outer space have few superimposed loads on the walls (once far beyond the nominal gravitational zone) however, if gets converted into stresses. The stresses ultimately result into some form of kinetic energy disturbing the equilibrium of the craft or station. To maintain the equilibrium (position and location), occasionally course-correcting boosters are fired.

Coventry Cathedral Ruins Flickr ImageOpenings like doors and windows, and provisions like niches, alcoves, weaken a wall. For reasons of load-bearing capacity of a structure, openings at lower level must be fewer of smaller width. Lower sections of structures, however, have lesser solar exposure, so more openings are required. Openings are placed one above the other so as to leave uninterrupted vertical wall masses to transfer loads directly to the ground.

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