Comparison and Analysis of Lightweight Steel Structure Residential Housing

Comparison and Analysis of Lightweight Steel Structure Residential Housing

Abstract—The   lightweight steel structure residential building has properties of the green, energy-saving, environmental protection and etc.  In the  past  few  decades, there have been a growing interest in the use of cold-formed steel structure  in all aspects of building construction, and in many   developed   countries,   there   have   been   significant developments   about   cold-formed   structural   building. However,  in   some   developing  countries, lightweight  steel structure residential building just started. In this paper, we introduce   some   properties   of   lightweight   steel  structure residential buildings and the current research situation. On the  basis  of  them,  we  analyze  and  study  lightweight  steel structure residential buildings in North America, Japan and Europe   in   detail,   and   give   their   some   features.   Then according   to   China   particular   conditions,   development status and properties are introduced about lightweight steel structure   residential  building,   including   some   traditional housing  concept,  and   intensive   steel  residential  building. Based on above investigations, some suggestions and countermeasures are given. It is believed that it is significant and helpful for promoting China housing industrialization.

Keywords-   lightweight   steel   structure;   component; residential building ; cold-formed structure; low multilayer

I. INTRODUCTION

With  the  development  of  the  construction  industry, changes  in  building  systems  and  construction  materials has   become   the   current   trend   in   the   development   of residential buildings. In recent years, due to the continuous improvement of people's living standards, they have  higher  requirements  for  the  housing,  stability,  etc., especially for low-rise residential, there  is an urgent need for   research,   development   and   promotion   of  beautiful styling, excellent structural performance, use of convenience, construction speed, economy and reasonable residential building system to replace the existing architecture.

Light  steel  structure  housing  is  based  on  economy steel members as the load-bearing skeleton, using pressure plate or sheet material as a lightweight wall envelope, and high-strength   bolts   and   other   connectors   and   sealing materials will   be load-bearing   components,   building envelope components such as on-site   assembled prefabricated residential building class [1].  It can be seen that the main building material for the light steel structure housing is  the  galvanized  lightweight  steel  keel as  major structural   components,   the   most   important   advantage using  this   material   is   that   you   can   guarantee   a   good residential    properties,   but    can    also    ensure    that    the constructed  house  with  a  dead  weight  light  weight,  high degree  of  prefabrication,  construction  speed,  small  labor intensity   of  the   advantages   [2,3].  Light   steel  structure residential  housing  compared  with  the  previous  tradition has the following advantages: a stable structure; low cost; span  light  steel  structure  villa  house  space  than  concrete buildings span; galvanized steel corrosion resistance of its use  can  be  excellent,  durable,  use  life  is  long. However, light  steel  housing  in  China  is  still  in  the  development stage. There are still some serious problems in residential design  process  to  need  further  study.  To  this  end,  this paper  analyzes  and  compares  light  steel  residential,  and introduces the characteristics of foreign and domestic light steel housing. And we give some reasonable suggestions.

The paper is organized as follows. Section 2 describes the characteristics of light steel housing abroad. Section 3 describes the current development of China light steel and steel   residential   housing   characteristics.   Conclusion   is given in final section.

II.    LIGHT STEEL HOUSING ABROAD

A.     North American Light Steel Housing North American  light steel housing is  from a wooden structure with lightweight wooden structure characteristics. In  the  North  American  residential  market,  they  account for 20% of the share [4]. Housing skeleton is mainly cold- formed  C-shaped  steel  keel  system  and  usually  one  to two-story   villa   housing   built   in   the   high   incidence   of earthquakes in California and other regions. Some of light steel housings in North American are given in Fig .1.

In reality, this  lightweight steel system has been very mature  in  North  America.  Now,  they  can  build   multi-storey  residential building  using this  technique  from  five layers to six layers. It is worth of mentioning that the most active  part  of research  in  the  US  is  on  cold-formed  steel structures.   The   reasons   for   this   are   the   expanding   of supporting  industry,  especially  in  the  area  of  individual family dwellings and rise of the cost of wood. Thus, steel framed  houses  become  more  and  more  economical[5]. Pekoz  [6] states  that  in  the  USA, about  500 homes  were built  in light gauge steel in 1992. This number rose to 15 000  in  1993  and  75  000  in  1994.  A  further  five-fold increase   is   estimated   by   2002.   The   primary   framing elements  for  this  form  of  construction  are  cold-formed  steel  wall  studs  and  floor  joists.  Light  gauge  steel  roof trusses  or  rafters  are  also  used.  At  present,  the  United States  have  produced  such  a  keel  system  for  a  hundred companies. Among them, famous company is the Dietrich company, which is the subsidiary of Worthington Industrial  Company.  They   developed   DBS   system   for building  multi-storey  light  steel housing [4].  Using DBS technology  system  can  be  built  multi-storey  residential light steel structure. Its wall uses C-channel gypsum board on both sides and floor uses C-type light steel keel laying 20mm thick fiber cement board, and are filled with glass wool  insulation  spacer,  which  plays  sound  effect.  In  the United States, cold-formed C-sections are commonly used as  roof  truss  members[7].  In  reality,  early  purlin  shapes were simple lipped channels and Zed sections. The simple channel has  evolved  into  Multibeam  Marks  I,  II  and  III, the  latter having a  compound  lip. A  similar trend  can  be seen in the evolution of the Zed into the Zeta and Ultrazed shapes, as shown  in Fig .2[6]. Cold-formed members can be  produced  in  a  wide  variety  of  section  profiles.  The most commonly used  components are the C channels and the Z sections shown in Fig .3[10].   This lightweight steel in   North   America   exists   in   stand-alone   or  townhouse because of its poor sound insulation. To resist lateral wind loads   and   seismic   action,   the   U.S.   multi-light   steel structure residential system has two kinds of methods: the use of light steel shear walls or cross steel frame support structure. Light steel shear walls are generally arranged in the   household,   using   0.5   mm   galvanized   sheet   steel Mongolia  in  gypsum  board,  and  then  fixed  on  the  light steel wall studs, similar to the formation of shear stress in skin   structure   between   each   layer   there   is   a   special component  of  the  shear  wall  to  connect  the  upper  and lower  floors  to  effectively  transfer  horizontal  shear  and tension due to the horizontal force acting on the wall studs produced.  In   the   earthquake   zone,  in   order   to   ensure structural safety, the  support  of the  Cape  with  a  cross  is used  as  a  lateral  force  resisting  steel  frame  structure  to form   a   hybrid   architecture   system,   where   light   steel withstands the vertical loads and ordinary steel withstands horizontal loads. To ensure wall insulation effect, besides the wall studs filled with glass fiber, a  layer of insulation on the outside wall material is pasted.  Using this method effectively  cuts off thermal bridge  from the wall studs to the wall panels.

B.     Steel Sheet Residential Construction In Japan

As Japan is an earthquake-prone zone and lightweight steel    has     good     characteristics     of     seismic     effects, lightweight  steel  is  locally  popular.  In  accordance  with their  own  unique  characteristics,  Japan  build  light  steel housing, namely  Sheet  Steel housing, as  shown  in  Fig .4 below [8,9]. This structure uses new construction process, i.e.   uses   a   non-welded   galvanized   cold-formed   steel combination,  also   known   as   Steel  2  ×  4,   which   is   a residential craft with a plate rib structure. The structure is an  architectural form  from  former North  American. Wall panels  and  floor  is  built  by  using  wood  based  on  box. However, in sheet steel housing, sheet material is replaced with steel, whose thickness is 1.0 mm or so. In two sides, lightweight   gypsum  board   is   affixed.  By   this   method, overall structure’s performance such as stable, durability, thermal insulation, sound insulation properties and etc., is achieved.

In   reality,   this   steel   sheet   structure   building   is   a construction which combines the strengths and advantages of   steel   and   plate   ribs   process.   The   building   entities’ experiments      demonstrated    that      it      has    excellent performance    characteristics    such    as    the    seismic    of resistance,   wind   load   performance   and   anti-snow   load performance. In 2003, the Japanese’s construction material is  changed  from  wood  to  thin  steel  keel.  Aiming  at  the architectural   features,   building   codes   in   Japan,   special instructions when building set automatic fire extinguishing and     automatic     exhaust     system,    internal     decoration reduce household heat transfer between the walls.

C. Energy-Efficient Residential Building In Europe

Germany began to implement the new building energy specification from 2002 [9]. Its core is the quantification of energy   consumption.  The   energy   consumption   of  each house  is  required  to  provide  building  energy  calculations to   the   competent   authorities   as   necessary   documents houses. It  has  a major impact  on  the  country's  residential development  and  building  materials  market.  In  energy- saving residential buildings, Sweden uses renewable energy  as  far  as  possible,  including  wind  energy,  solar energy, geothermal and other energy sources, and integrates these technologies. In short, European countries more  focus  on  the  study  of  energy  efficiency  and  green building.   Now,   cold-formed   steel   components   can   be rapidly and accurately assembled into complete structural units for delivery to the site. In the UK, most out of town hotels  and  motels  are  now  built   in  this  way.  The   UK construction  industry  currently  uses  over  300,000  ton  of cold-formed steel products annually, and this consumption rate is growing steadily[10].

III. LIGHT STEEL HOUSING IN CHINA

A. The Development Status Of Light Steel Housing 

For   a   long   time,   housing   construction   is   mostly dominated by concrete in China. It is no longer suitable for the  theme  of  today's  green  buildings   as   it  needs  large materials and long construction period.  As China has been the  largest  producer  of  steel  in  the  world  since  1996,  as shown in Fig .5, the state government started to encourage the   use   of   steel   in   civil   engineering industry.   With construction  steel processing  industry  growing up  day by day, steel structure construction in China has stepped into a high-speed developing period [11]. from concrete structure to ordinary steel building and from ordinary   steel     building    to    light      steel     structure. Development of steel residential building does not pursuit advanced technology and special tools and should focus on mature,  integrated  and  practical  housing  technology  like the  European  countries. In the process of integration,  key is the detailed structure and mutual convergence.

Since  light  steel  components  easily  are  produced  by factory with high degree of mechanization, high degree of commercialization,  and   fast  construction   speed   on  site. And it does not affect nearby residents and the construction of civilization favor is very high. Light steel is an environmentally friendly, sustainable development product and its comprehensive economic indicators are not higher  than  the  reinforced  concrete  structure.  Therefore, light   weight,   good   seismic   performance   of   light   steel building must  become  the  mainstream in  the  construction industry.  Now,  building   is  experiencing  the  conversion

B.    The Characteristics Of Light Steel Housing

Light   steel   is   a   new   concept   at   first.   With   the improvement   of   people’s   living   standards,   it   gradually goes into people's lives. In China's some major cities such as Beijing, Shanghai and other places, light steel structure residential  building  has  been  established  by  introducing technology from North America and  Japan into China. At present, most of the light steel housing in China belongs to light  energy-saving housing construction  which  uses steel frame    structure,    light    wall,    light    floor,    light    roof construction system. Using ordinary H-beam welding steel, small section of hot-rolled H-beam or straight section steel and combining anti-profiled wall lateral force factor, multi- layer structure  can be  built.  And  it  is  consistent  with  our current      specification      system    and    meets    seismic requirements  [9].  In  2011,  China  issued  and  implemented the   "low-level   cold-formed   steel   building   construction technical  regulations",  which  combines  the  cold-formed steel keel system in North America and promote this keel system. In the process of designing using C-channel cold- formed   steel   and    U-shaped   steel,   load-bearing   walls consist of column, top and bottom guide beam guide beam, support,  brace  and struts, wall panels  and  other structural components  [12],  as  shown  in  Fig  .6  below.  Despite  the provisions of the relevant specifications, but this structure is  still not  large  popularity. Although  light  steel structure has some advantages, for example, light weight, excellent seismic  performance, short  construction  period, structural stability  and  other  characteristics,  but  it  also  has  some problems  to be  further addressed, such  as  large  noise  and poor   refractory.   This   short   construction   period   of   the building  is  now not  be  recognized  by  the  people  and  its safety and reliability is not verified.

But  this  light  steel  building  is  the  development  trend  of China  architecture  and  needs  more  researchers  study  its safety, reliability and durability. In a word, China is at the beginning   of   lightweight   residential   buildings   of   steel structure  and  has  a  long  way  to  go.  Compared  with  the developed countries, there are a lot of questions and China still  lacks   behind   a   lot.   It   needs   to  be   improved   and perfected continuously [13].

C. Recommendations And Strategies

As  lightweight  steel structure residential housing is  of good  performance,  light  weight,  high  degree  of  factory, construction  speed,  low  labor  intensity,  etc.,  it  gradually developed in the United States and Europe in the last three decades  and has  created  a  set of very mature  technology. Now,  many  domestic  and  foreign  enterprises  invariably want to migrate light steel structure residential technology to China, but  they do not make  sense. The  reasons are  as follows:
 

1) There isn’t systematic lightweight steel specification.

Although the "cold-formed steel structure technical regulations"  was  promulgated  in  2011,  but  it  is  hardly consider making major load-bearing components with steel thickness  2 mm  or less. For system of plating zinc  metal frame bearing with the extensive use of wall thickness 0.8- 1.6  mm  abroad,  neither  theoretical  analysis  nor  relevant experimental data of the structure exist, which makes light steel structural design very difficult in China.
 

2) Society as a whole requires a process to accept this new housing system.

People are still very strange for such a  structure  and  they  still  poorly  understand  its  security, stability, comfort and etc.

3) Project cost is high.

As the technology is still in its infancy, the  lack of skilled  workers  and  the need of light steel components introduced from abroad incur the higher housing prices. To solve the above problems, the following recommendations and strategies:

1)   To improve lightweight steel specification, constructing a  number of pilot  projects makes  this  aspect of   technology   gaps.   Large   enterprises   with   doing   this research in this area should be supported.

2)  On  the  basic  of  construction  of  pilot  projects  and obtained  experience,  one  should  seize  the  opportunity  to prepare   the   corresponding   light   steel   structure   house technical standards and codes.

3)  Once   the   technical  standard   is   promulgated,  the technology      system      should      be      incorporated      into professional schools as teaching content.

4)   Some   of   the   successful   experiences   of   foreign countries   are   absorbed.   Aiming   at   specific    situation, scientific  research is conducted. States should make some policies  to  support  the  research  of  this  technique  so  that light steel structure is popularized step by step. By means of  this  method,  it  hopes  that  more  people  will  recognize this structure.

IV.    CONCLUSION

In    short,    low-light    steel    multi-storey    residential building in China has good prospects for development with less  materials,  small  pollution,  short  construction  period and   in   line   with   the   development   trend   of   domestic architecture.  It  will  become  a  new  situation  of  China's residential     buildings.     With     promulgation   of   steel residential building technical guidelines and specifications, low  light  steel  residential  multi-storey  must  also  further developed.  By  absorbing   and  improving   technology   of light  steel  structure  system  abroad,  increasing  production capacity  and  capacity  development  of steel  technology,  I believe   light   steel   structure   will   be   widely   used   and developed in China.