Report on mountain retaining work

Along with the revision of the Yokohama City Building Standards Law Enforcement Regulations, from construction that starts on or after April 1, 2013, submission of "construction plan for mountain retaining work" etc. Submission is required.

In Yokohama City, at construction sites such as detached houses on slopes, sufficient consideration and preparation for temporary construction of mountain retaining were not carried out, resulting in slope collapse accidents and dangerous situations on nearby sites. Cases have occurred.
In order to prevent the occurrence of such dangerous situations, Yokohama City has revised the Yokohama City Building Standards Law Enforcement Detailed Regulations, and will be subject to submission of reports on mountain retaining work that had been requested by construction builders or construction supervisors. We decided to expand the scope of construction.

1. In addition to the property that has been issued a certificate of confirmation by the Yokohama City Building Manager, the property that has been issued a certificate of confirmation by the designated confirmation inspection organization is also subject to submission.
2. Documents to be submitted are subject to change.
   • When performing root cutting work with a height of more than 3 meters and 5 meters or less
     ⇒Outline of construction plan for mountain retaining work
   • When performing root cutting work with a height of more than 5 meters
     ⇒Construction plan, etc. for mountain retaining work

When you perform root cutting construction about building and public establishment which received certificate of confirmation by Yokohama-shi or designated confirmation inspection organization, please submit required documents to City of Yokohama, Housing and Architecture Bureau according to the following. ( Regardless of whether or not there is a structural examination at the time of confirmation application, submission is required if the following applies.)

1. Construction work and documents to be submitted
   • a. When performing root cutting work with a height of more than 3 meters and 5 meters or less
     • Outline of construction plan for mountain retaining work (Form 1)
     • Guide map
     • Summary of the mountain retaining plane (describes the site boundary, height difference in the adjacent land, the location of the retaining wall, and the status of the surrounding site (location, scale, structure, road, railway, etc.)
     • Cross-section (root cut height, difference in height of neighboring land (if there is a cliff, angle and height of the cliff))
   • b. When performing root cutting work with a height of more than 5 meters
     • Construction plan for mountain retaining work (Form 2)
     • Guide map
     • Mountain retaining floor plan (site boundary line, height difference in neighboring land, positional relationship between core and mountain retaining wall, situation of surrounding site (position, scale, structure, road, railways, etc.), location of entrance yard, temporary equipment Location, location of construction machinery, installation location and import route of construction machinery, location of work on road, etc.)
     • Cross-section of mountain retaining (root cut height, difference in height of neighboring land (if there is a cliff, angle and height of cliffs), root length, foundation form and foundation position of the neighboring building)

   ※（b） If you fall under the category and the use of the building is a detached house, please submit a structural statement such as mountain retaining. However, even for other purposes, if it is necessary to confirm the safety of the retaining work, you may be required to submit a structural statement such as retaining work after submitting the construction plan for the retaining work.
   ※When performing root cutting work over multiple steps, draw a 45° line (main working slip line) from the bottom position of the bottom of the mountain retaining at the bottom of the mountain retaining bottom, and if there is an upper part of the line, Please use the sum of the height from the bottom to the top. (Refer to the figure below)

2. Date of submission

   Please submit at least 7 days before the start of root cutting work.
   ※ If it is necessary to submit it before issuing the certificate of confirmation, please submit the confirmation number columns of Form 1 and Form 2 blank in advance. Please fill in the confirmation number at a later date and accept it officially.

3. Submission address
   • In the case of buildings and structures other than those listed below
     Building Guidance Division, City of Yokohama, Housing and Architecture Bureau Building Guidance Division Building 25F
   • In the case of retaining wall (work) that has been issued a certificate of confirmation in Yokohama City
     City of Yokohama, Housing and Architecture Bureau Residential Land Examination Section (in the case of adjustment area section) City Hall 25th floor

   ※ Even if you receive a certificate of confirmation at a designated confirmation inspection organization, be sure to submit it to Yokohama City. It cannot be accepted by the designated confirmation inspection organization.

4. Download the form

   Please download the form from the link below.

   • Outline of construction plan for mountain retaining work (Form 1)
   • Construction plan for mountain retaining work (Form 2)

<Reference> Article 17-3 of the Yokohama City Building Standards Law Enforcement Regulations