Chapter Title and its name on middle of page

Question

I use following code for sectioning of my title page of thesis. First two chapters title and chapter number is in mid of seperate page and text is started from next page,but next chapters start from top with text. Can any one guide me in this regard.

\usepackage{titlesec}

\usepackage{titling}
\usepackage{lipsum}
\titleformat{\chapter}[display]
{\normalfont\Large\filcenter\sffamily}
{\titlerule[1pt]%
\vspace{1pt}%
\titlerule
\vspace{1pc}%
\LARGE\MakeUppercase{\chaptertitlename} \thechapter}
{1pc}
{\titlerule
\vspace{1pc}%
\Huge}
[\newpage] 

Answer 1

Here is an attempt

\documentclass{report}

%\usepackage[showframe]{geometry}
\usepackage{titlesec}

%\usepackage{titling}
\usepackage{lipsum}
\titleformat{\chapter}[display]
{\normalfont\Large\filcenter\sffamily}
{\titlerule[1pt]%
\vspace{1pt}%
\titlerule
\vspace{1pc}%
\LARGE\MakeUppercase{\chaptertitlename} \thechapter}
{1pc}
{\titlerule
\vspace{1pc}%
\Huge}

\begin{document}


\begingroup
\titleformat{\chapter}[display]
{\vfill\normalfont\Large\filcenter\sffamily}
{\titlerule[1pt]%
\vspace{1pt}%
\titlerule
\vspace{1pc}%
\LARGE\MakeUppercase{\chaptertitlename} \thechapter}
{1pc}
{\titlerule
\vspace{1pc}%
\Huge}
[\vfill\clearpage] 

\titlespacing{\chapter}{0pt}{-2.25ex}{0pt}
\chapter{First vertically centered chapter}
\lipsum
\chapter{Second vertically centred chapter}
\endgroup
\lipsum
\chapter{normal chapter}
\lipsum
\end{document}